When i was in the first trimester, i had the same difficulties. The best thing i can suggest is to stock up on hospital grade Sustagen (i got mine from a pharmacy), because it's a 'thick' milk and lines your stomach, it can turn down the hunger for a few hours. Also containing all the nutrients you need.
I had troubles eating right up to sixteen weeks, but got addicted to cheese, lettuce and tomato sandwiches!