Tinnitus with post nasal drip could be due to sinus infections or ear infections, which are a result of untreated post nasal drip. If you are experiencing these symptoms only when you are at home, then there should be some thing you are allergic to causing these symptoms. As, you mentioned you are allergic to dust mites, they cannot survive in a humidity less than 50% in the environment, but their fecal matter can be the culprit causing these allergies in your case.
Disodium octaborate tetrahydrate powder is often used to eradicate house dust mites. Hope this helps. Best.
I will try using that powder, thanks for that info. Would it help me to take some kind of antihistamine? I have not had a Dr. give me any advice about how to get rid of the post nasal drip. I tried a nettie pot with salt solution, didn't work. I also used nasal sprays with no result. Is there something you would recommend?