So My period ended last week and things have been fine since then. But I woke up a while ago and about an hour or two later I started having crams. I feel like I'm on my period but I'm not. I am not sexually active whatsoever so idk what's wrong with me. My legs hurt like hell and my lower back has a sharp pain. And for a bit there was a pain in my stomach but it has subsided. I feel sick and have a headache too. Is this anything serious?