Welcome to HealingWell and to the bipolar forum.
It may be that your girlfriend is no good for you, but it also sounds like you need to visit the doctor. Are you being treated for your bipolar? Do you see a doctor? Are you taking any medications? Your inability to follow along with reality -- to keep track of what's going on for real -- is part of a symptom of advanced mania. You need to check in with your doctor and get it treated very soon. You won't lose your child if you go to the doctor for help.
Feel free to ask more questions if you need to.
Co-Moderator, Bipolar Forum