Guaifenex and exhaustion

I took one pill and fifteen min. later I started having a pain in my stomach. I thought, well maybe I didn't eat and drink enough, so I drank another glass of water even though I'd eaten a good size meal before taking med. Five min. later the pain switched from stomach to chest and back pains, but mostly in my chest. Also, my finger nail beds turned blue and I could not get warm and had chills. My heart did not seem to be racing and was steady, though I did get a mild head ache. At the peak of the pains it radiated up my neck and lower jaw, and no matter how I lay I could not make it go away.

I experienced a sudden feeling of overwhelming exhaustion during the whole ordeal. Symptoms persisted for a few hours, didn't stop until shivers had passed and by then I had a temperature of 100.7 when I previously had none whatsoever. I think about 96.6 was my average before that. The next day I was extremely tired and unaccountably restless.

The only other med I had been taking was a 24 hr. Alavert that dissolved on the tongue... it didn't even have a decongestant in it. CVS lady said there was no reason I couldn't take it along side the Guaifenex. Now I'm not sure what to believe. It scared me enough that I don't think I would ever risk taking it ever again.