I’ve heard those things as well (don’t take a bath…don’t eat cold things).
I don’t know if they have any bearing on your period…I haven’t felt any. I don’t follow any such restrictions. I take warm showers and I eat cold things. NO adverse side effects so far, AH. The only “changes” I’ll try to make is to take a multivitamin that contains iron…and I’ll try to eat healthier.