Personally, I'd burn somebody's house down...

wow

selfish

Don't ditch your old friends but try to find a few new friends that do enjoy the things you enjoy. Never let anyone keep you from being yourself. Also be frank with your old friends. If you haven't done so already, and find out who stuck a tack in their seat. Tell them you are sorry they are depressed, but you are not ready to give up living out of sympathy for them. You have to go forward with your life. Figure out a way to do so. They will get through this phase, but you can't support them if they won't let you breathe. And you have to be straight with them about that.

Having been on both ends of this issue multiple times, I have to ask how you have responded to them? The first step to knowing what to do with a situation is knowing what you are dealing with. I realize it is hard to be on the receiving end of these attitudes. If you could hang on a bit longer, try to find out what is going on and what has triggered these mood swings in your friends. Quite often, negative flips are triggered by depression, anxiety or stress. Your friends may not even realize they have become negative, or this may be their cry for help. They may just feel embarrassed by a problem they are having or that they can't burden others with their issues. Opening up the lines of communication (gently yet firmly) can open up both of your eyes. It can also deepen the relationship, trust, and connection during the process of solving whatever issue is going on. I would suggest trying to get to the root of the issue. So often we get busy and take the easy way out of a situation. Taking the hard road does have its rewards though. It makes you a deeper, better person and can gain some true, lifelong friends.
There may be an element of danger in this as well. If your friends in unsafe situations (deep depression, abusive/unhealthy relationships/situations, substance abuse/addiction, cutting, suicidal tendencies), you may be that friend's only link to help and healing. To write love on her arms is a really amazing organization from everything I have seen, heard, and read about it. http://www.twloha.com/
Sorry for the long response. I wish you the best of luck and lots of strength and hope. Your friends may need you more now than ever before.

However, I should note something here. If you approach this situation, it must be from a selfless, giving place. If you don't genuinely want to help these people get better and grow, they would be better off not getting help from you. A selfish approach only leads to more damage and hurt. I am not trying to sound mean, but it is the reality of the situation.

completely agree with everything you said there couldnt said any better myself!!

I know how you feel..:/