No, you don't. I have a friend who changed to vegetarian during her last pregnancy and got plenty of protein and everything. Talk to a nutritionist, take supplements, read books, there might also be good websites to help you plan your meals to get the right amount of vitamins and minerals and protein.
No you don't have to eat meat. But you need to make sure to get your protein and iron still. So yes, talk to someone and get maybe a list of good substitutions!
Make sure you take your prenatals and that they have iron in then (the gummy ones do not) and extra protein. Nuts have a lot of protein, I eat a lot of trail mix :)