What Causes Red Bumpy Rash On Bottom, Arms, Back Of My Legs, Under Neck And On Ear?

I am 23 years old an have never had a rash. Tonight i realized that I have a red bumpy rash on my bottom, arms, back of my legs, under my neck and on my ear. The rash does not itch really bad but it is tender. Tonight I also had black stool. I have not eaten anything out of the ordinary today. And the only medication I'm taking is Dilantin for a seizure I just had 3 weeks ago. Last but not least... I have no health insurance. Please help.