Kind of freaking out

26 weeks pregnant & ive been having dizzy spells like no other. Twice when I was trying to fall asleep & could only fall asleep if my face was pushed up against my SO back & I had to be looking up. Then today we were FINALLY gonna have sex & I went down on him & I started getting really REALLY REALLY dizzy but I pushed through it because we've only had sex twice during my whole pregnant 😂 but after we were done I had to go straight to sleep because I can't stand to be dizzy. I've been having hot flashes like no other as well. Now that I'm up I'm not as dizzy as I was, but I am dizzy if that makes sense. But I seriously don't know what to do.