Hi there - I'm pescatarian, so eat fish but not meat. I have been absolutely fine getting the essentials with my diet during pregnancy. Iron levels have been fine (that was the one thing that did worry me), but I have been taking the Sanatagen supplements since TTC and will probably keep taking while (hopefully) breastfeeding.
I get plenty of protein through the fish I eat, plus nuts, plulses, etc.
I have upped the amount of cheese and milk to make sure I get enough calcium as I wasn't eating as much dairy as I should have before pregnancy. I actually didn't really like dairy - and during the first trimester it make me feel very sick. Since then though, I've really enjoyed extra yogurts, cheese, etc... So maybe my body did need that extra!
So long as your diet is healthy and balanced, I don't think being vegetarian is a problem in pregnancy.