I second what maleficent said. I was
vegetarian for many years, and I wasn't watching my protein intake very carefully. I'm almost positive I wasn't getting enough. Now that I'm tracking everything I eat, it's amazing to see how much more protein there is in meat than in other sources like soy. Dairy and eggs can both be good protein sources in addition to soy for vegetarians.
Other than that, it's not really that hard to find meat substitutes. If you're cooking for yourself, no problem. If you're going out to eat, most asian places have tofu dishes, and many American restaurants have things like veggie burgers.