I go back and forth between craving things and then not being hungry at all, no food aversions, just a "I don't know why I should eat because I'm just not hungry" feeling. The other night we were eating out and I was trying to remember what the chicken tortilla soup from this one place tasted like and I couldn't recall it even though I had a craving for it just a few days prior. The only thing I could imagine was the taste of a gyro so we went to the greek place instead.
This is how I am too, one day I am famished and can't stop eating, the next I can't bear the thought of eating anything at all.
In my first pregnancy I couldn't get enough salted limes-- I would eat three or four at a sitting-- but my dentist was quite stern about the damage I was doing to my tooth enamel. This time I have the same craving but satisfying it with shots of real lemon juice. I also can't get enough cucumbers, sliced in apple cider vinegar, and again, heavily salted. I had major salt cravings during the first trimester of my last pregnancy too, and no resulting health issues, so again, I am just going to succumb to the craving.
And I am with nettlesoup on the fish kick. I stocked up with canned fish (clams & oysters, mackerel, sardines, smoked trout) and I have at least one can a day-- I guess it's all good since I'm getting a heaping helping of those omegas...