Realistically, periods make me tired, especially the day right before. Not helplessly tired, just if I had the choice I'd probably rest that day, though I can do stuff if I have to. My periods tend to start out heavier and get lighter, which I understand is fairly normal. On heavy days, there might be some pain/discomfort, but it's entirely manageable. Women around you every day are working and going about their lives while menstruating. If a period is exceptionally painful, there could be a medical problem. I use a cup, and most of the time I barely know I'm menstruating. It's just an extra little chore to take care of.
Historically, many women simply sewed their own washable pads, and some women still do today. So she might need to stop somewhere to wash her pads out, though any fantasy character probably handwashes their laundry.
Mood changes do not happen for most women on their periods. While some women do experience hormonal mood changes, this is a subject you want to be careful RPing, unless your goal is to be offensive. Do some research, or post your email and we can talk. Mostly this is a stupid stereotype. And PMS is PRE-menstrual syndrome, meaning it happens BEFORE periods.
I don't really get why this subject gets such a strong reaction on both ends. I think it's pretty cool, and I like pictures of menstruating women. Dudes who think it's sexy are okay by me. I wish the ones who wanted to experience it for themselves could, though I think some of them might be let down by how boring it is.
Also, orgasms do help, I masturbate with my period and it is very relaxing. The cup adds a little stimulation, like using a toy. I've had period sex, and it's a lot like regular sex except if you know neither of you has STDs you don't need a condom. It didn't feel "wrong" to me. Wasn't even very messy. We put a towel down.
I think people who have problems with periods, whether they're men or women, really just have problems with women.
