Eating meat again after being a vegetarian for 5 years?

I'm trying to go back to eating meat after almost 5 years of being a vegeatarian. I already eat fish but I just tried eating a piece of chicken from a Banquet microwave meal and now I feel sick and I only ate like one bite. So how should I go back, like what are the proper foods to start out w/? Best brands? And what can I do to stop my sick stomach??