Had black stools today should I be worried?

Likely not. Wouldn't worry about one episode, may be dietary related. If however they persist and you have other symptoms (abdominal pain, dizziness) need evaluation to be sure you do not have gastrointestinal bleeding.
R/O GI bleed. If this is just one time, don't worry, it might be what you ate. But if it has been long standing, these tarry black stools most likely mean you have a GI bleed, more likely upper, but can be anywhere. A full check of your GI tract is in order to locate the bleed. An endoscopy and/or colonoscopy would help to do this. If this persists, see your doctor to find and repair that GI bleed asap.