Hello agrin: I see this is your first post here on PC. Welcome to Psych Central.

I don't know as there is a lot I can suggest to you with regard to your concerns. I do know reaching out for the help one needs can be really scary. And there are always lots of unknowns & rationales one can come up with to avoid doing what one needs to do. But at some point one simply has to "rip the band aid off", as I have heard it said, & do what needs to be done.

If you feel you simply can't talk to your mom, perhaps consider talking with a student counselor if you're in school, or talking to your family doctor. Could some of your fears actually come to pass? Sure I suppose they could. There's always that chance. But if you're skipping breakfast & lunch as well as purging your dinner, something's not right. And the sooner you address it, it seems to me, the better. So I hope you do. And, in the meantime, I hope you find being here on PC to be of benefit as well.

Here's a link to an article, from Psych Central's archives, on the subject of eating disorders:

Eating Disorders: Symptoms, Types & Treatments | Psych Central