Just sharing some of my wife and mine experience..
1. After your first missed period, you can use a pregnancy test kit to check first. If you get a positive result, you can start looking for a doctor. Unless you've been trying to conceive for more than a year, or you are over the age of 35, it's not really necessary to see a doctor before your pregnancy.
2. Eat normally. Do get folic acid supplements though.
3. dont't really understand what you are asking here.