Recovery from mental illness, how to show my friends how I feel?

It sounds like this was a very difficult time for you and if your 'friends' couldn't understand that or be there for you at such an important time then I don't think they're really worth it. But if you miss them then I guess it's worth a shot, but like you said you've made new friends so if your old ones still don't understand after you explain the situation then it's obviously their loss. Goodluck :)