Sex ?? Kinda tmi

I am 30 weeks and TMI I just tried to have sex with my SO and yes we had lube lots of it and sometimes it just starts out uncomfortable but it was just so unbearable that I had to jump up and go to the restroom. I understand that this happens late in pregnancy but I didn’t know it would be happening already... could it be for a serious reason I should look into or is that just kind of normal around now ?