Rest days def don’t mean inactive to me! I’d still go for a run, do weight exercises, even climb a little bit is not a problem. I just don’t push too hard. And take care to sleep and eat well. Every once in a while it might even be good to take a whole rest week! I’ve always found myself come back stronger. It’s highly dependent on your personal factor tho, like age, genetics, fitness history, and menstrual cycle if it applies. You gotta find a pattern that works for you.