HELP PLEASE I’m having extreme butt soreness

Okay, so I am an adult who has pretty light periods. I am also a bit over weight. This is something I’m working on, but I have a little extra fat in some places. During my period I get extremely sore kind of in the area between my butt and vagina. It kind of feels like the “chub rub” that I some times get between my thighs. All I want to do is stay as still as possible. In that area my butt hurts to touch. It’s hurts to sit, walk, go to the bathroom, and exercise. I’m so uncomfortable and I have a demanding job. I cant just be still because my butt it sore. What can I do? I prefer not to use tampons but is that my only option? Thanks for the help.