If your girlfriend commits suicide, does that mean you don't matter to her or she didn't care about you?

Not necessarily true: It is understandable how a boy friend of a girl who committed suicide might feel that way but it certainly may not be true. There are many other possibilities including the fact that she may have had an overwhelming mental disorder. It would be very helpful to such a boyfriend that he see a mental health professional and have an opportunity to explore his thoughts and feelings about this tragedy.