Valcat, you really need to get the physical side of this addressed NOW. I'm very sorry that your T seems to be dismissing this as "merely" a SI thing, because -- while it may be in large part SI related -- the physical consequences can be life threatening! What's more, the immediate consequences are fairly devastating, too. For one thing, without proper nutrition, you can't progress in therapy! Not "won't", not "aren't likely to". You physically can not think when you're in an eating disorder like this. The physical side of it affects your cognitive ability, and you simply cannot progress in therapy until your nutritional status is normalized.

Hard as it is, go see a GP, get checked out -- and then find an ED specialist or someone with more experience with EDs to get evaluated.

If you want a reminder of why it's important to do this, even though you like your current T (which I'm assuming you do), remember this: Terri Schiavo tried to get help for the bulimia which caused her heart failure -- and the doctor dismissed it.