Avoiding medications

I dont know what category of eating disorder this falls under but whatever. I started avoiding medications because i was scared of gaining weight, checking medications for calories even knowing they wont have any but just to make sure, and i completely stopped taking my vitamins which i have been told i need to be on. Im easing my way back into medication to some extent but i cant for the life of me go back to the vitamins because i am so certain they are going to make me gain weight