First of all, kudos to you for understanding Bipolar Disorder. Many people don't understand what Bipolar people go through. The constant second guessing, beliving that you aren't good enough for the world, etc.

Secondly, has your gf seen her psych or therapist in a while? To me, it sounds like she might need her meds adjusted/changed or she might need to spend some time with her therapist working on proper coping skills. There have been many times, for me personally, when everything just gets waaaaaaaay too overwhelming and I just can't handle, well, anything. Since I have learned the proper coping techniques and my medication is currently working, I've been doing pretty good.

Why don't you try to contact her and tell her that you truly do love her and that the two of you will work on this together. Many Bipolar people in crisis feel that there is nobody in the world that actually understands what is going on in their brains. They don't reach out for help because they feel that they don't deserve help. I always thought I could do it alone, but I'm finding out that you need to have a vast network of support, good positive support.