I can identify with that! I had that when I was spinning after my first baby (9.6lb preemie) I luckily didn't have to get my plumbing put back, well, not yet anyway.
I increased my stretching (hip flexors, low back, it band) and made sure my posture was pristine. This is hard to do if your instructor is less than phenomenal.
I know half the fun of spinning is trying to kill oneself with increased tension but maybe that isn't for you quite yet. It also never hurts to get checked out by your OB to make sure there aren't any ovary issues.