How seriously do you need to take painful contractions during sex?

This is my fourth pregnancy, and during my second one I always got regular contractions after sex in the end of the pregnancy, but they stopped within one hour. Except once when I was 35 weeks and it started labour. I had to go to the hospital and they were able to stop my contractions.

In my third pregnancy I also got a few contractions after sex in the end of pregnancy, but never went into labour because of it.

Now I’m only 23 weeks, and we just had to stop sex because I got such painful contractions that I’m now lying in bed with a heating pad on my belly. It actually felt like labour contractions, and I felt pain ”down there” on the inside, like in my cervix I think. This pregnancy it started already when I was around 12 weeks pregnant, and they have been much more painful this time.

Should I be concerned?