Menstrual cup cramping

Hey ladies!

I just got a diva cup to try out. So far, I love it! The only downside is the insane cramping I'm getting while using it, almost to the point where it hurts to move. I'm not sure why.. I don't cramp up nearly as bad while using tampons.. I don't particularly want to switch back to tampons/pads, but the pain is miserable. I'm still new to using the cup, but I'm pretty sure I inserted it correctly! Any advice?