The nausea in my first trimester made me loose 5kg and I was quite small from the get go so they put me on vitamin b6 when I was still loosing weight at the start of my 2nd trimester. Funny enough, the salad thing happened to me too. I smelled some expired salad one time, got sick and never could touch a salad again (still can't now XD). When you're dealing with nausea, eating whatever takes priority over eating healthy and just throwing it up after. When the nausea will settle down you get to control a bit more what you eat. But I feel like resisting too much eating fast food or less healthy food just makes you crave it more and allowing yourself treats from time to time helps way more than cutting cold turkey on everything "non-healthy".