TMI but i need advice please!

Tiffani
Okay so I was just sitting in the chair and all the sudden I felt crampy almost like I was gunna have the runs so I went down to the bathroom and actually went to the bathroom (wasn't the runs) but now my lower back keeps cramping every so often and I'm kinda crappy not too bad thou. But I never had braxton Hicks with my first so idk what they feel like I'm only 18 weeks so I'm a little worried. Also earlier me and my SO did the deed and I had to have him stop cause it started to hurt like up where the baby is like sharp pains idk if this could be related? Sorry for the details