Perhaps you should hit them up yourself for a change, call them instead of texting and organize to do something. Friends do not have to hang out with each other all the time, they may enjoy their solitude every now and then.

To help your hair grow it must be healthy, so no hair dryers or straighteners, keep it clean, don't use hair product so much and go to the hairdressers to trim the dead ends off every couple of months. It will grow, just give it time.