Bipolar what I've found anyway is we fall fast. Care deeply and can be a roller coaster for the person we are dating. Our moods can bounce from extreme sadness where we should know that you care about us but it feels like no one would give thoughts if we just vanished off the face of the earth. I'm not sure about everyone else but my depressions aren't always the same. Some can be literally earth shattering for me where I'm at my lowest and cut ties with people because I feel like it would just be better that way no one would have to worry other times it's me just feeling lonely. Just ask her what you can do for her when she gets into a depression. Does she have manic or hypomanic? You need to clarify with her what your course of action should be for if and when she has an episode. I can't stress that enough. My ex would send me into worse states by saying the wrong thing or treating me poorly. So just keep your ears open and your eyes open because it's a hard relationship to be in but rewarding.