Rash on my stomach?

Annelise • 26. I have a 4 year old and 3 year old sons & baby girl born Dec 6, 2019
Wtf is on my stomach? I just felt the need to itch my stomach an lifted my shirt. It's bumpy an very red. I have no idea where it came from. I'm 27w and not sure what I should do. I've never gotten random rashes like this. My husband thinks it's a heat rash but I'm in a room temperature room an it's freezing outside so that makes no sense. Plus I've never even had one of those. Idk if I should be freaking out but I kinda am. Any advice or help is greatly appreciated