17w5d and worried about my baby?

I go in on the 25th of August for my anatomy scan. I'm so excited because this is the first appointment my fiance will be able to go to. I'm also kind of scared because they said they will be able to detect any abnormalities. I know this is stupid but I haven't been eating healthily at all. I'm ashamed to admit it, but I haven't. I work in a fast food restaurant as a manager 11-15 hours a day. I'm rarely hungry and when I am, I eat something small, like some fries or a small burger, then I'm done. Sometimes that's all I eat all day. When I'm home, I sleep pretty much the whole time because I'm exhausted from my job, so I eat a bowl of cereal. I do a good job taking my vitamins and eating some fruits & drinking milk/v8 juice, but I'm afraid that's not enough. Everyone I work with who has been pregnant said that they never had this problem. They ate healthy, balanced meals and were never really not hungry like I am. So... are there any of you out there who didn't eat healthily like you should've and still had healthy babies?