Making new friends at an adult age is different from making friends as a child... because of the usual view on life most adults have. I dont know how old you are, but i assume you'd be above 16...
I think you may have been doing one thing incorrectly.. you were too uptight, too scared to lose friends, too scare to somehow push them away from you, that you kept thinking "i dont wanna lose this friend... i'm scared they stop liking me..." what you were actually doing, was sending vibes to the universe about LOSING friends... so the universe gave you what you, albeit inadvertently, asked for.
But chin up, YOU can change things around. Instead of focusing and stressing about finding good friends, try clearing your mind of worries and think about what makes you feel good. Remeber times when you were happy and be happy for it. Start doing something that you always wanted to do, or that you used to do, but stopped. SPorts? social groups? choir? cooking groups? woodworking groups, walking groups, start a new course in school, university, technical school whatever. If i didn't mention something you'd wanna do, YOU know best what it is... go for it... Dont just do it thinking "Now i HAVE to find a friend" no, just enjoy yourself and send good vibes and you will attract likeminded people. You will be friends with someone not because you WANT to be friends, but because you will resonate in similar frequencies...
I have been lucky to always have good friends, but i never tried to BECOME a friend with someone just for the sake of it... it happens naturally, when you relax and when you send positive signals out there...
hope this helps...
let us know how you're progressing!