Just got a BFP, Now I have a question...?

So my husband & I just found out Christmas morning that were pregnant (I have PCOS so this is a big deal for us!!) but I've had a weird rash on my neck & chest for the past 2 or 3 days (& I have not changed any thing that I could be allergic to)...I'm going to get into the Dr. as soon as the weekend is over but I was just wondering if any one could tell me this has happened to them?? An allergy to a hormone? Just more sensitive because of the pregnancy? I don't know? I'm probably about 5 1/2 weeks...