Your allergies sound quite severe. In the long run, you will want to see an allergy specialist for more advanced treatments for your allergies. You don't want to take a Zyrtec every day for the rest of your life without getting input from a specialist. With that said, I can not tell from you description whether you are suffering from an allergy flair or if you have caught a virus and have an upper respiratory tract infection. The two syndromes can be very similar. The best way to tell is the pattern of symptoms. If you have no new exposures to allergens, but get a runny nose, cough, and feel run down, then a viral respiratory infection is more likely. If you get a runny nose, cough, itchy eyes, that improve after taking your Zyrtec, then it is more likely an allergic reaction. Another way to distinguish is by a head and neck exam by your primary care physician
. For this reason, I think you should schedule an appointment. The appearance of your nasal passages are different if they are responding to an allergy versus responding to a virus. The distinction is important because of treatment. A viral infection will pass soon without treatment while an allergy will not (if you are still being exposed to allergy). You may need additional allergy treatment other than just the Zyrtec.