I haven't been eating much and I'm losing a LOT of weight. This isn't a good thing because I'm already underweight. But I feel like i force myself to eat and it makes me feel sick so i usually just skip meals. I know I need to eat properly but I'm a fussy eater and genuinely don't have an appetite. I can't really word my question right... But what should I eat for dinner if I'm hungry but don't 'fancy' anything?
What you need to do is stop being so damn picky. If you don't like what's on the table, make something yourself instead of starving yourself to the point where you lose a lot of weight. You need to eat. If not, you will lose your hair and become energy and nutrition deficient and you can die. Being picky isn't a good excuse not to eat.
Take up some fairly intensive physical activity, like aerobic exercise or whatever. A half hour of that every day should help you develop an appetite. But do NOT overdo it; especially not before you have begun to put on some weight.
You may try some carrot juice.