Is it possible that my allergy med Zyrtec D is drying up my cervical mucus?

I'm TTC but have noticed that I don't have any CM. I've checked my cervix but still no mucus. I got a positive on an OPK yesterday and today and I had ovulation pains yesterday I'm just not getting any CM. Is it possible that the Zyrtec D is drying up my CM? I take the zyrtec d once every twelve hours and I can't stop taking it because my allergies are too bad and end up causing sinus problems if I don't take my med. How can I bring my CM back? Any help is appreciated. Thanks.