Severe Cramps - help!

Ha

I am having terrible cramps this month, worse than I can ever remember. They’ve always been bad but this is unbearable. They’re not being touched by Tylenol and I can barely get out of bed. They’re very strong and have eased up for maybe 2 hrs total all day. We are currently TTC & I had an ultrasound appx 1 month ago with no sign of cysts. Could this be endometriosis? Would that have shown up on an ultrasound? I’m grasping at straws here.