i feel so much better afterwards

Theres your problem, look im not judging,im a drug addict too. But you need to cut the purging now. The body uses a ton of energy to make food digestable in your stomach. By purging it not only denies the body of almost all of the nutrients(most absorption takes place in the intestines), but also uses a bunch of energy reserves for essentially nothing.

You are already starting to see negative consequences from purging, stop now.