M.B.
G.,
I took Benadryl many times during pregnancy. I can't take decongestants due to a reaction and my only option when sick with a cold or allergies is an antihistimine. My son is just fine as well. I currently take Zyrtec every day and my doctor assured me that if I get pregnant again this drug is also fine. Unfortunately Benadryl may make you sleepy so try to take it at night.
Good luck
M.