Cramps in the night, should i worry?

I'm TTC and am currently in my 2WW, anyway i posted a question yesterday about an odd pain (as if my trousers were too tight and digging into my lower abdomen) so last night i couldn't sleep but obviously nodded off because i was woken up with stupid painful cramps, they went as fast as they came but i was a bit shocked. I've never had any sort of cramping the 2WW before. Has anyone else had this and got their BFP soon after??