Diagnosis: Hives

I spent 2 hours last night at urgent care.  I had to wait a bit because the doctor was running late and then I had to wait for the results of blood work.  My CBC and liver enzyme tests came back normal, but I had high levels of eosinophils, a type of white blood cell.  High levels of eosinophils are indicative of an allergic reaction.  So I am, in fact, having hives on my skin from an allergic reaction.  The doctor told me that claritin and benadryl are both safe to take during pregnancy and so I've been using those to alleviate symptoms.  But when the drugs wear off, the hives come back.

I don't know how long these hives are going to last.  I think I may be allergic to Endometrin (the progesterone suppositories) because I started them last Tuesday night and the hives started on Thursday morning.  But I stopped taking the suppositories on Saturday morning and switched back to the progesterone shots.  So why am I still having an allergic reaction?!  I would have thought that the hives would have subsided by now if they were due to an allergic reaction to the Endometrin.  So I'm still trying to get some answers from the doctor I saw at urgent care.  Is it reasonable to think that I'm still having a reaction to the Endometrin even though I stopped taking it on Saturday?  If so, how long can I expect to have this reaction?  And if the hives continue, then what?  Then it means it's not the Endometrin and I have an allergy to something else in my environment.  So do I need to see an allergist or pregnancy specialist?

I'm really worried that something is wrong with this pregnancy.  I have the irrational fear that I'm allergic to this baby and my body is rejecting it.  I hope that is not the case.  I'm having my second beta tomorrow and I'm crossing my fingers that the number increases appropriately.  My doctor is also going to test my estrogen and progesterone levels because I'm having some brown spotting.  The RE says this is not normal (despite me reading many many blogs of women who have brown spotting (or even bleeding!) and go on to have normal pregnancies).  I'm nervous.