forcibly vomiting can cause tears in the esophagus that will result in bleeding. you could see this in the vomit. bright red blood seen in vomit is more likely to come from the esophagus than the stomach. dark red or black looking blood may be partially digested, and therefore more likely to come from the stomach. either one is concerning, and would ideally be seen by a doctor.
i hope you are doing better now.