Eating disorder help

I think I have an eating disorder. I’ve kinda been in denial about it for like almost a year but I’ve been with my boyfriend for 2 months now and since i spend a lot of time with him he has noticed that i eat very little and he is really worried and is always saying that he wants to help me and that i need to talk to someone and seeing him being like actually scared that I’m not eating nearly enough has made me realize that I need to do something about it. I just don’t know how to do this, like how do i start? Ive tried eating more and more everyday in little steps but i feel like when i take one step forward i always take two back.