question

so my uterus has been feeling really weird the past week my period is suposed to start in a week but last night I had sex then masturbated and when my uterus would contract I felt a sharp pain in my uterus I have an iud its the mirena I've had it almost a year and havent felt this before is it normal does anyone experience this?

every now and then it feels like little flutters in my uterus and my vagina