You are off to a great start. 5X5 is a great beginner program and imo the best way to get your beginner gains. There is also another closely related routine called Ice cream fitness which some people prefer. Eventually, you will want to taper off this once you get the beginner gains. I'd recommend getting a trainer for a 1-3 months to get your forms down, if you can afford it.
If you are just starting to get healthy, counting calories can be a bit much. You don't want to overload yourself when building a new habit like working out consistently. I'd just follow some simple principles.
Avoid sugars such as Soda, Coffee with syrups, candy and the like.
Avoid alcohol completely if possible. I still enjoy beers socially, humans are weirded out if you don't drink with them. However, I never drink alone.
Always eat before going shopping, this will prevent you from buying extra goodies you might not necessarily need. The easiest way to not eat bad food is to never buy it at the store. If you know it's in your house, you will eat it.
Try to eat outside of your house less. You don't know how the food is being prepared, how much oil, salt, sugar, etc. is in the food. You can't always avoid this but having a high ratio of eating out vs. at home helps.
Some additional random things
It's a process and you shouldn't don't compare yourself to anyone other than who you used to be.
No one at the gym is looking at you. They are so busy in their own routine.
You should find a playlist that amps you up on your way to the gym. You want to train your brain and body to be ready to fk things up when you step through those doors.
If you are severely overweight, everyone that is really fit in the gym is rooting for you. We know the struggle, and we know how hard it is to make a change for your health. If you think people are laughing at you, it's in your head. Again, people are into their own routines.
If you see a big guy at the gym, don't be afraid to ask him for some advice. They may look scary, but I promise they are just regular people and are usually weirdly friendly.
Muscles don't grow unless you overload them. If muscle is the goal, your going to need to push yourself.