24 weeks and horrible rash?

I have a rash all over, but only on my stomache. They are a bunch of red dots spread out, and itch horribly especially around my belly button. I don't have stretch marks. But its quit annoying, I'm wondering if I should be worried or have others gone through this? I've tried everything, every anti itch, every lotion, and even changed my laundry to non perfume and for sensitive skin. I have a doctors appt next week. But has any other mom been through this before?