I am 32 weeks pregnant. And I have really bad heartburn everytime I try to lay down to sleep. I also have a really bad rash on my wrist what is it?

Tums/elevate bed. For heartburn, chewable Tums work well. Zantac is next step, or a prescription like protonix (pantoprazole). Elevating the head of the bed works very well too. For the rash, that's a different concern and you should ask your OB to look at it.
Eating behavior/skin. Please avoid laying down after a meal or filling up with fluid. That places pressure on the stomach & increases backwash of gastric juices. Avoid caffeine, chocolate or nicotine. Using OTC omeprazole may help. The skin rash could be many things, needs an exam.