Lightning crotch? Tmi

im almost 29 weeks and all night/ morning now ive felt this sharp stabbing pain/pressure way down there every 20-40 mins regardless what position I lay or stand in. I don't want to call and bother if its normal but I don't want to go in to work and stand for 8+ hours if it could potentially be effacement or something? I've seen people say its just baby going down (still scary it feels way too soon) but other people say that that's what early labor felt like. 😱

The hubby and I did have sex last night, could that cause this kind of pain?