Keep some cheese cubes or slices in the fridge and a healthy trail mix in your purse... nibble on it to ward off nausea... you don't need extra calories until about 15 weeks at which time you will only need 300 extra calories per day for the duration of your pregnancy. That looks like half a Peanut Butter and jelly sandwich (just to give you an image) I studied nutrition in college and took an interest in pregnancy nutrition also I am currently 18weeks... If you let your head tell you that you have to eat more you might gain weight. I am 18 weeks and still loosing and my OB is not concerned. You might not be able to see a midwife because of the surgery but good luck there are a lot of things that have to be done differently. This is my 3rd pregnancy and it is being handled very differently :-)
