What Causes Persistent Vomiting?

Hello. I Wanted to get some advice on this flu or food poisoning condition that i may have. I started throwing up at 9 pm last night and couldn't stop going to the rest room. I started dry heaving at one point but then I started throwing up a dark brown liquid. I started drinking sips of water and couldn't keep that down for more than 30 minutes. My boyfriend has the same thing too. I currently haven't thrown up since 7 am and I'm feeling a bit better I just feel a little bit nauseous. Any advice on what you think this may be?