For me, two things help:
1) Recognizing what is going on. Seriously. Once I recognize it and realize it's PMS, that takes a lot of it away, and I feel like a different person.
2) Premsyn. When I start feeling crazy and like the walls are closing in, and I realize what time of the month it is, I'll take a couple. Rarely more than once or twice. Usually I don't need to, if I pay attention to #1, above. I don't know how this would react with your bipolar meds - you'd want to check first.
Definitely, definitely talk to your doctor.
The Warrior Princess: 2008 Jamis Xenith Pro / Bontrager Affinity 1 (men's)
2006 Trek Fuel EX 9 / Bontrager Race Luxe
2007 Trek 520 / Serfas Terazzo
Amelia Pond (She travels long distances, has great adventures, and she's a redhead): 2007 Trek Pilot 5.0 / Bontrager Affinity 2 (men's)