I'm on day 2 as well. I've done this twice before, but it has been a while. And, I guess it doesn't get any easier. As for your questions. I recall reading that it's O.K. to chew on peppermint leaves to ellivate bad breath and I believe taking vitamins is out. Your lemonade has everything you need. Vitamins are usually not recommended.
Hopefully we'll both get through this. After day 3 or 4 it's usually a lot easier.