If you think its blood you need to go the ER. You don't have to have eaten something red to throw up red. Sometimes the mixture of everything you HAVE eaten and drank can make a weird color combo, but if you are unsure if it is blood or not, I would def. go get that checked out right away.
this happened to me. I would call your DR. I kept throwing up and I threw up so much I was irrating my throat. it was blood. So call your nurse or dr and explain what has happened. Everyone is different.