This is a hard one for sure. It always comes down to taking care of ourselves when we cannot handle our own life struggles. This might sound selfish to you but it isn't. If you don't think that you can be around your mom right now.... how are you going to help her? Does she have others who can support her? I think you will be there for her when the time is important enough. Right now a time out might just be the cure. Be gentle on yourself.