Get fit, work out. Working out helps make you more confident, you feels SO MUCH better about yourself. Try to get better hobbies, get involved in your community, Itll be easy to meet people and make friends ^{^}

As for the stutter, try to work on your social skills while volueentering, try to fake your confidence than it'll eventually come naturally :) That's how I went from a bit of a loner to having multiple friends! You have to see outgoing~ It's hard but you can do it! You seem like a good person, and aren't ugly what so ever. Also READ the book defining decade, it helped me forceably change my life.

You will never be in your 20s AGAIN, make the change now or you'll regret it! :D