I'm somewhat in the same boat as you - 3/6 schools done sending invites, good amount of research experience. This is what has kept me sane (ish).
* if there is a chance that I have an interview, I better have my paper submitted by then so that I can show it *
basically, set a goal that you need to focus on, so that you can't wallow. What you do now with your time will probably have an effect on your apps still. easier said than done (lol I'm on gradcafe right now) but it's all about steps forward!