If you want to be alone right now, then for goodness' sake be alone: you cannot be peer-pressured into being social. So tell friends to go on and have their fun without you, you'll be fine. Right now, your friends hold a bit more influence over your life than they should, and it's probably a good thing to be without their influence for a while. You need to sit with yourself and look at the big picture. Figure out what it is that you want, not what it is that they want.