I've Had Diarrhea For The Past Couple Days And Some

I've had diarrhea for the past couple days and some abdominal discomfort. After lunch today, I slept for a few hours (doing shift work) and upon waking up I vomited multiple times, with the first 5 or 6 times having a dark tint, almost black, and a good amount of undigested food. Within the past month I've also had the flu and sinusitis.