Should I be concerned about brown-colored vomit?

[sklort]

I am a 17 year old female that weighs 170 lbs (a lot, I know I’m working on it), and after eating breakfast this morning I coughed up a little bit and there are brown particles in the vomit. Everything above is going to sound really dumb after I say this, but there was chocolate in the breakfast I had (pancakes). There’s still an underlying concern, though, because I feel fatigued, have a small piercing pain at the bottom of my sternum, and am a bit dizzy. I can’t tell if my paranoia about my health is causing a placebo effect, or if this is something I should truly go to the E.R. for. Additionally, I’ve had problems with acid reflux and recently, bulimia so I’m afraid the constant agitation of my stomach acid could cause some sort of hemmorage. I’m really hoping it’s just the chocolate and I’m being paranoid.

[CurfewX]

It's hard to tell, since this occurred on the same day you ate chocolate.  When people vomit dark brown blood, it is often described as looking like coffee grounds.  I wouldn't visit the ER based on this incident, but if if occurs on a day when you didn't eat something dark brown, it is worth having yourself examined.