Help me please,

So my period was suppose to start yesterday. But I never started. And well me and my boyfriend had sex the other day, and when he pulled out, I felt like a watery substance come out my vagina, but when we checked the condom I wasn't broken or anything, well atleast there wasn't any sign. What do yall think about this? I'm worried. Cause ever since that day my stomach has been feeling weird.. and about two days ago I got this really really bad pain in my stomach. And white stuff keeps coming out of me???? I always think it's my period but it's not. So what do yall think?