The light headedness can just be from what your body is going through. If you aren't eating or drinking enough water that can do it too. Have you tried popsicles? Warm broth can give you some protein and you can put noodles in it for a little more staying power. Oatmeal is great too. If it sounds good then try it.
Keep it up with the tylenol and watch that fever. If it gets too high it can be dangerous, but you are already on top of that.
You can do your best but pregnancy lowers your immune system's ability to fight off infection. No amount of vitamin will fix that. So its just a risk you take being pregnant. Wash your hands and clean the surfaces in your home regularly. You don't want to re-infect yourself later.
Just keep trying. I know its miserable, but you are doing the best you can.