I have bulimia and i have been throwing my food up for a few months now. i am starting to see blood..how bad is this?

This is serious.: You are clearly damaging your body. Strongly encourage you to seek prompt medical care. You need to be 100% honest about your purging with your medical provider. If you have significant vomiting of blood - that would be a medical emergency that requires immediate evaluation. Please see a therapist who is experienced in working with eating disorders. Take action now.