Early labor ?

My bf & i had sex about 2-3 hrs ago. I keep having really bad pain in my abdomen amd back along with pressure. I also have this stomache ache as if i have to go number 2. But when i go sit on toilet it doesnt come out. What should i do?

P.s yes i am aware that cum makes you contract alot but this is different pain than ive experienced before. Currently 33wks & a few days.

UPDATE :

Theyre gone lol but boy them contractions were something serious. I told my bf, no more sex til after babys here cause i cannot. Lol but thanks everyone for the advice. Water deff helped.