I can relate alot too. At 21 I felt like I missed out on alot of things including being a "normal" teenager and all the things that go with that.
For a while this made me feel completely powerless and frustrated because I wanted to be better and start living life but I wasn't and didn't know how to.
I guess that it takes some degree of recovery to get the point where you recognize what you've missed out on, so it's a positive thing!
I sort of grieved for the time I lost and then vowed for the next 8 years not to be the same. It's about trying to rebuild your life, but it's difficult if you've been ill and don't have a normal to go back to - so it's going to be a long-term project
So I just took little steps, trying to think of things I liked and doing them. Breaking the bigger things into smaller steps. Began volunteering and that helped to give me some confidence, going back to study, setting silly targets like seeing one person a week. Two years on I have abit more of a life, but it's still quite limited. However I have studied, am earning a little bit of money, have a few close friends I see every now and then!
Dunno if any of that helps....