I live by a philosophy: Don't get greedy. Do your best.
In my 20s.. I thought too much. So much I'd get lost in there. So much I'd have entire relationships with women before even knowing their name. SO much that I would create scenarios and play out the entire thing in my head before it happened. So much that I barely slept and when I did, it was the only peace I had.
I was in college and felt like a "grownup" yet not. I had to work, I had to go to class. There were things I just had to do, but what constitutes being "an adult"? I wrote about it here: http://www.confessionsoftheprofessions.com/children-pretendi...
Anyways, you are in your 20s. I am now in my 30s and I wish someone would have given me advice that I could've understood then. But this might be something of what I would have told myself:
You are still exploring life and it is perfectly okay to make mistakes -- so long as you do no serious harm to anyone or yourself. You get this life to live. That's it. There are many other people who won't make it past their 20s. I hate to say it, but it could be your close friends. Mortality is all too common and all of us can and will die.
Do not take any moment for granted and just teach yourself to be aware of your surrounding and other people. Don't always talk about yourself. Listen to what others have to say. Travel. Learn how to take care of yourself (some exercise and good eating required) because you get one body to live in. Don't think about it. Just do it. Know that you will fail at a lot, but you will also learn a lot. You will have successes in many of the things you do as well.
Try to call your parents at least two or three times a week. Try to keep in touch with your siblings at least two or three times a week. Go visit if you can. Go explore. Volunteer for a few months and do some good in a community. Go live in another country if you can. Teach English. Get a degree in something. Study something you want to know more about. Don't be afraid to ask any girl you want out. What's the worst she is going to do? Tell you no. She's doing you a favor. When looking to be with someone, it is not all about sex. Find someone who makes you happy and who is pleasant to be around. Find your best friend. Here is the worst part of the advice: Don't look for it. Don't look for her. Just be aware that a girl you like could be her. Just enjoy your life. She'll come eventually. Go on a few dates and don't be afraid of letting her know what you are looking for. You need to experience the opposite sex to know what you like and what you don't like. To do this, you need to learn how to become comfortable with yourself and develop a sense of humor and you need to become comfortable with being around people, especially the opposite sex.
Make sure you pick up skills that are valuable for the next decade or two. College only helps you get so far, but you're going to find out that you aren't special when you and everyone else have a degree in Liberal Arts or English. Sure, you'll get a job, but it'll probably be a job you don't like. So pick up a hobby and learn about something you like and start thinking about what you could do to help others that will also help pay the bills. Learn how to talk to people. Learn how to interview. Learn the difference between telling people something and telling them what they want to hear.
Coming back to the point about don't get greedy and do your best: be fair with pricing, if you decide to ever charge people, be fair with people. It is also okay to donate to charity or help out a homeless person or people who are struggling. Don't do it to the point where you become homeless yourself or forget to take care of yourself, but go talk to a person who is "down and out" and understand what happened. Everyone has a story to tell. You'll be amazed at just how human that person is.
You are going to go through a bunch of jobs you don't like, but learn how to deal with them. Don't get comfortable though, because you won't be staying. You are learning to deal with and tolerate bullshit. Keep moving on until you find a job you love, but aim to be your own boss.
Most of all: stop overthinking. It doesn't change anything. You need to find a balance between thinking and doing. Go for a long walk. Go for a hike. Learn how to meditate. Calm your mind. It does not always need to be thinking about something. Definitely know that you aren't the only one going through it. If you ask your friends, they will likely agree they do it too.
Always be ambitious and trying to aim to do something good with your life that will help not only yourself, but others. We're all trying to "progress to that next level" but really, there is no levels. We all pretty much just keep going and maybe even pretending that we know what we're doing. We really don't. But as long as we keep trying, we'll be alright.
Everything is going to be alright.
Finally, I listen to a lot of music, and while I love Pink Floyd and it has gotten me through the toughest times of my life.
There are three songs that truly helped me understand life's philosophy:
You can't always get what you want (but if you try sometimes, you get what you need).
If you can't be with the one you love, love the one you're with.
Don't worry, be happy.
This is all part of life. Everything you are experiencing. You may have anxiety or depression or feel insane... and to live in our world, you need to have those. Accept your flaws and use them to get to the next day, to each and every day, for the rest of your life. From every moment that seems like a failure to every moment that is a success. Keep going. I've lost friends and best friends who never made it out of their 20s. My mission is to keep on going to experience what life is like, what it could be like, and what it is. I don't just do it for myself, but I do it to live a full life for them, because they will never get to have that chance ever again, at least as themselves.
Life is too precious. We shouldn't be alive. We are rare to live on Earth at this time in the exact spot that we do that supports our lives. We are all going to be dead for way longer than we are alive, so we need to be appreciative and enjoy the life that we were given. You will only be you once. Never again. Whether we talk of heaven, hell, or rebirth: you will get to be you once. Make the best of being you.