lower back ache after sex?

Jade
I'm 11 weeks + 4 days pregnant and had sex  this morning and now I have a lower back ache. It's not painful just feels like that dull feeling you get when you are on your period. There's no cramping but I'm really worried. I also sneezed after and had a horrible pulling pain and heard and popping noise (which I'm unsure whether this come from my bottom or somewhere else 🙈).