Is this being caused by allergies?

My symptoms started when we got our second dog. I am allergic to dogs but have built up an immunity to our first. I did not think my allergies were bad with this one because i was not do the usual sneezing, itchy throat..But know i have all this pressure constantly in my nose, behind my eyes and constant drainage but no relief and also I get head rushes if i move to fast getting up. I have seen my regular doctor and he said take claritin for a week and if not better to see ENT. The claritin makes me feel like i got hair in the back of my throat. YUK!  Anyone know what I am talking about? Is this caused by my allergies?

[National Jewish Health]

Your pre-existing allergy to dogs makes it quite likely that your allergy symptoms and nasal/sinus congestion are due to your being allergic to the new dog.  However, it is also a possibility that your symptoms of sinusitis are just a coincidence.  You might want to totally separate yourself from the new dog for 3 to 7 days to see if you improve.  You might also ask your doctor about symptomatic relief whether the problem is dog allergy or not with the addition of an inhaled nasal steroid and a decongestant, to the Claritin® (loratadine) or another antihistamine that might not give you the irritating side effect of Claritin® (loratadine).  Your physician might also want to consider obtaining a CT scan of your sinuses.  You might also want to ask your doctor what the ENT specialist could likely add to your care.

Good luck.