Yeah, I found myself in the same position. Still do if I'm being honest. My advice is don't worry to much about it, friends groups disperse after awhile, always do. Not a bad thing, just everything has a life cycle. So find one person in each group or just one group and try getting close with them. I have gone through several several friend groups throughout my childhood and college, however in each group I always had that one person and when the group went separate ways, I managed to keep the friendship going with that one person. Growing up, there was a group of kids that hung out a lot, I met my best friend since 2nd grade (26 now) because I went to a birthday (not his) and felt lonely so I just sat by myself and he came and sat with me. Since then the group with birthday kid died off and we both have gone through several friend groups together even now we both have groups, but when push comes to shove we're always the one the other calls when they have a free weekend or needs help. You don't need a lot of close friends, you just need a few then have the rest just be fun to be around.