Sure, no man is an island, but it's inevitable that people come and go. Those who stay forever, you'll never really know.
It's a hard mix, I think. You don't want to be distant/anal, but you also don't want to get hurt.
So I guess it's just important to do things for yourself, and do what makes you happy. If u don't hurt anyone, there shouldn't be anything stopping you. Love yourself and respect yourself. And while you're at it, learn to not give a shit what people say and think about you. I've learnt that it only matters when your lovers do.
This is starting to sound lame.
Just remember: life is a long twisted game, so do what YOU want.
PS: this is not to say you should get rid of your besties, i just think you should make yourself your number one BFF.
..anndd goodbye! xx