I just entered my 3rd trimester. How much more calories should I be eating daily now for 2?

You can have a read at this article: http://www.whattoexpect.com/pregnancy/calories-diet/ As a guide, you may need an additional 500 calories in the third trimester. However, there are many factors that comes into play. The article also mentioned that you can use your weight gain as a guide. So, if you conceived at a normal weight, during pregnancy you should gain about three to four pounds during the first trimester, then about one pound per week in the second and third trimesters. Personally, I would say don't think too much. Have a balanced diet and listen to your body. Don't be too stressed about this. :)