Allergy pregnancy. There is no category one medication for pregnancy as no drug can be tried on pregnat humans, category two means the drug has been tested in animals and no bad outcome was detected, you are in 7th month and baby is alredy grown, you can try saline nose spray and if you need meds consult youe OB doctor and may take Claritin (loratadine) or zyrtec which are both categoryb or old type of antihistamines chlorphenarmin.
OTC antihistamine. Some otc antihistamine, such as claritin, (loratadine) zyrtec have pegnancy class b status, which means they are relatively safe in pregnancy. Also, 7 month is far out of the first trimester, which means the little one is big enough to be more resistant to possible harmful effect of drugs. When in doubt, consult an allergist locally or your ob.