Try not to freak out. It's probably just an allergic reaction to something. Go and see the doctor and tell him/her everything you ingested. Remember, they're not law enforcement, but they need to know what you ate in order to fully understand what may be ailing you. The first thing any nurse, doctor or paramedic would tell you in your situation is to take some Benadryl, which is available over the counter in any drugstore anywhere, to suppress your histamine (allergic) response.

By the way, just because you've eaten something all your life doesn't mean you can't develop a sudden allergy to it. I'd eaten strawberries my entire life, too, and then two years ago, boom, they caused a bad allergic reaction. You have to have had at least one previous exposure to a substance, in fact, before you can even develop the antibodies to have an allergic response to it later.