Diarrhea for almost a week!?

I was recently on vacation to the beach when I was eating a lot of fast food and more food than usual anyway. I was at a resturant and I ordered a steak cooked to medium and afterwards I just felt full and bloated after eating which is unusual for me after that I shoved some ice cream down. I'm very fit and I don't usually eat this much. When I got home that night I had a very cold feeling and I assumed it was from the ice cream but it lasted until morning so I'm thinking it was a slight fever, but that was it. Ever since all my stool has been is loose watery diarrhea. When it started it was very often now mainly in the night it wakes me up. But no other bad feelings except the gas and a little kramping and discomfert while eating. What do I do please help?!