My doctor told me not to take my allegra (fexofenadine) and zyrtec 5 days before my skin allergy test but my symptoms are really severe. should i just take my meds?

Reschedule: Your appointment for skin allergy testing if you have to take the antihistamine, otherwise bear with the symptoms till done with the test. I'm not sure what your symptoms are, if nasal symtpoms, saline nasal wash and steroid nasal spray can control your symptoms and still get the test done. Otherwise blood testing can be performed instead, more expensive though and results take time to come back

Talk to Allergist: If it is not possible for you to stop antihistamines before your allergy appointment there are blood tests that can be drawn instead. Skin testing is more sensitive so it is preferred by myself and most allergists. I would call their office and discuss your issues so you don't show up on antihistamines and have to reschedule.