If your having the same problem monthly around the same time each month then I would say its your hormonal shift because you do have your ovaries. I had a Hysterectomy in 2001 and they left my ovaries in hopes I would not slam into menopause. My hormone levels are up and down a lot test me on say Monday and levels are ok , test me a week later and my ovaries apparently are on vacation and appear to be entirely useless. I tried low dose Hormonal replacement , but I chose not to take due to all the problems they can cause.

If your hormonal levels are okay ,, Then it's probable its just one more "gift" from Bipolar

Good luck