Itching, red skin, hypotension, fatigue, feverish, difficulty breathing.?

Skin started itching almost 2 months ago. I was prescribed zytec and it seemed to do the job until now. I have recently been experiencing the itching skin along with fatigue, hypotension, difficulty breathing and extremely dark red skin that comes and goes. I also often look pale and recently I am feeling feverish. The doctor gave me an inhaler, a shot of steroids, and a very strong antihistamine. However, the steroids seemed to do absolutely nothing and the antihistamines are not working either.