Everyone has these problems dude. It's perfectly normal and as you get older you stop beating yourself up (to some degree) and focus on the things you do well and slowly you realise maybe you aren't the best, but that you are a high quality person, in different and interesting ways from everyone else.

It's no bad thing to experience some bad times and feel these feelings from time to time - what I've found with myself is when I get to this point I have an automatic "fuck this shit" response where I, for example, move to Japan to work full time on startup ideas. Sometimes when stuck in a rut there is no harm at that point saying "fuck it" I'm just going to make a big exciting change and see what happens.

Another example; I can't even swim really (more flailing, should probably learn) and I was in the Andaman Islands on holiday and everyone was diving and I basically panicking when I put my head in the water with a snorkel on, what was I thinking signing up for Discover Scuba. So after managing to get over that initial fear, I ended up signing up for the full PADI and then did my advanced on the same trip because I loved it so much. I cleared my mask and swam sharing oxygen at 25 meters (while looking at the under water equivalent of Avatar). That fear turned into pure excitement for life.

So if you want to be less in your analysis mode - my advice - get out of what you are doing now and make a big change, whatever is (and even if it doesn't work out) while you are trying life will taste a bit sweeter.