It's normal. Just try to eat what you can and your appitite should come back before too long. Just make sure you're eating good foods and you're taking your prenatals.
Ok hun I know exactly how you feel. I have had morning sickness since about 6 weeks and I am now 10w 3d & I still got it! I have no appetite for anything, especially lately. Mine is probably from the nausea. But even when I am not nausueous (SP?) I still don't have an appetite but I know I have to eat so I do but I get super full, super fast. It's a bit frustrating :(
What I do is not push it first of all. Then I'll eat a 1-2 hours later again cause I am hungry again. lol. So even thought it is such a pain to do this, I think the key is small meals about 6 times a day and try and eat healthy. Prenatals shouldn't effect your appetite but who knows all these weird things happen to you in pregnancy, especially now, your bodies getting used to it and your HCG levels are through the roof. If the prenatals are affecting you try and talk to your doctor about the flinstone gummies for now, I am taking them and there milder for right now for me.