Cramps

The past three days I've been getting lots of cramping in my lower stomach and lower back.. yesterday my cramps were so bad I was crying my eyes out from the pain it was worse than period cramps.. I'm 15 weeks pregnant. I had no bleeding or spotting or anything. I think it might be from UTI because my pee is very cloudy and I have had LOTS of discharge that's yellow colored and my bladder always hurts. Has anyone had these intense cramps and was it from UTI or should I be seriously worried? I have a doctors appointment coming up so I've been trying to just wait it out but yesterday's cramps made me want to go to the hospital but they went away after I laid down flat on my back for a while
Update: thanks girls 💗 I'm seeing my doctor today