What Causes Fainting Spell With Loss Of Peripheral Vision?

I have a few things wrong with my, I have a rash on my neck that hasn't gone away for two weeks now, sometimes what seems like an irregular heartbeat and yesterday I experience large black spots in my visions, loss of peripheral vision, then going down to pinpoint vision. During all of this I also was very hot, and began to sweat alot. I could not stand, and would have almost fainted if a girl in my operatory did not lay me down in a chair (Im in dental hygiene school), I also was very pale and then after about 5 minutes got extremely cold.. do you know what this is?