Crippling pain in stomach

I've got the coil for 2 years now.

Ive just had sex with my partner, went downstairs to get some water and each step with my right leg the right side of my stomach would be in so much pain, like a huge stab, I thought it might have been trapped gas but its not, it came so suddenly, the more I walked the more sick I felt and the pain moved to my lower back.

I'm in bed now lying on my stomach as its bloated out and thought it would help but it's not, pain is still there but not as bad.

It's 2am so I'm not going to the hospital, I'll see how I feel in the morning. Any ideas of what might have happened?? This has never happened. Period is due in just over a week