No one can tell you what your problem is, and don't let them try! Only YOU know why this is happening, a bit of introspection is what is needed.
do some yoga or some stretching, sit in a quiet place and relax. focus your eyes on a burning candle or close your eyes. Have the question in mind but don't try to figure it out, just look at what is happening... eventually it will come to you.
I dont know if you should listen to someone as horribly twisted as myself, but you should do what you want, and your friends are yours to choose.
You push them away for your protection of being hurt
Some people have a few or only one close friend. Others like large groups of friends. It's just a matter of personal preference.
Just be true to yourself and honest with everyone else and no one will get hurt.