You have most probably god some food infection, HBV is highly unlikely because symptoms are rare and do not appear so quickly.
If you are so worried about your health do not eat shawarma at all, it is known source infections.
You chance of infection is very very low. I agree with above poster that you either had food poisoning or it could have been your nerves.
If i discovered blood in a sandwich I think I would have gotten sick as well.
If you are really worried, you could wait a few months, then be tested
Take Care