Sex with boyfriend now light spotting?

So my boyfriend and I had sex around 8 or 9 pm last night. It’s now 1:30 am and when I just went to use the bathroom, very light pink blood showed up on the toilet paper. But not in the toilet. I wasn’t wearing panties, only black sweats so I can’t tell if I’d been sitting in it. I just put on panties and a panty liner just in case. I’ve been having really tight/uncomfortable pain in my lower stomach/vagina. But I can talk through it mostly. I just breathed like I have been for my BH contractions before. Is this the start of labor? I’m 39+5.