How do I gain weight?

I(22f) have a terrible relationship with food. I’m 5’4 & weigh 90LBs. I’ve never weighed over 100lbs in my entire life. I have trouble eating consistently and find myself either not in the mood to eat or disgusted by the thought entirely. When I do manage to stomach something it’s either fast food or unhealthy snacks. It affects my mood, I’m fatigued & cold all of the time. I want to change and be healthy. Does anyone have any advice, recipes or websites they could share?