Undiagnosed illness debilitating this 24 year old. Please help!!!?

I know you probably won't like this but it sounds very much like stress/panic disorder, the tingling can occur if you hyperventilate and it interferes with the blood chemistry which would also cause dizziness and nausea, as well as the heart palpitations, racing heartbeat etc. The blood pressure is more worrying as you are young to have it and although stress can make it worse it shouldn't remain consistently high. Drinking coke is not good as it is high in caffeine and that will just exaggerate your symptoms. As the prednisolone worked i would hazzard a guess that it is an autoimmune or inflammatory disease of some description as steroids do help with those. There are lots of little known conditions so it is unlikely that You would be able to find your symptoms matching exactly one of the better know ones. If they find nothing it could be that you have ME or something, maybe Menieres which would tie in with your ear and nose problem. hang in there, it sounds like your doctors are trying to get a hold on this for you. Best of luck