Braxton Hicks?

Tmi. I'm 31 weeks. So last night we had sex and I didnt even orgasm and almost right after my stomach got super hard and I felt so nauseous. My stomach stayed hard for a good 5-8 minutes and I was drinking water and laying in my side. Eventually I fell asleep and woke up during the night feeling fine. Can sex alone without orgasm cause Braxton hicks?