Ephedrine is the central ingredient in the manufacture of modern bath tub methamphetamine. If you were to take 60mgs of ephedrine and convert it to meth, it would get you very high. The way you are taking it builds tolerance, as you found out, and the same addiction issues as a meth addict. Detox of amphetamines definitely causes depression, but depression alone doesn't cause eating disorders on it's own.
Like mentioned above, you self-image was suffering before the ephedrine. CBT will be able to help you with redirecting your thinking and help you have a more positive view of yourself. The amino acid L-Phenylananine has helped many with amphetamine recovery. Personally, I would try some other nutritional options, before jumping straight the AD's or SSRI's. I don't know you or your doctor though, but drugs usually attack the symptoms, not the problem. If you are a danger to others or yourself, then drugs are a good idea, but drugs to help heal drug addiction is proven to not work. They can be used as tools in recovery, but they won't heal us. I know that normal was not how the psych meds I have taken made me feel. There are many other options to try before drugs, unfortunately few doctors know much about nutrition.
Depression can be treated with GABA, Tryptophan, SAMe, Tryrosine, Magnesium, breath work, meditation, therapy, lowering glutton intake, avoiding junk food, etc... Eating disorders are a whole other animal and I have never seen a drug actually help with it, though I have only known maybe 10 people with severe eating disorders. Therapy and lifestyle changes seem to be what has helped those I have known. i am not saying not to take the drugs, but it seems like you went from very health conscious and finding natural rememedies to synthetic meds pretty fast. I assume that is how you got hooked on ephera root, it is natural and creates energy, but you probably didn't know it is addictive. It is actually illegal to sell ephedrine in the U.S., accept a few products that are kept behind the counter and you can only buy one bottle of the cough syrup. Like I said, people make methamphetamine out of it.
I say focus on the eating disorder and try natural ways to recover, if that all fails or you are in risk of harming yourself or others, then start seeking a drug to help you. Keep us posted, this is a huge issue today, both eating disorder and people not realizing the addiction potential of herbs and plants. I would love to know how it works out for you. Remember, I don't know you, so this is strictly my opinion based on little info. Keep seeking, you will find what you are looking for.
from reading your post it seemed you were obsessing about your weight BEFORE you even started the ephendrine.
eating disorders don't just turn on or off. they grow like a snowball. you really need a good eating disorder clinic to go to because trying to fix it with medication alone is never going to work. there is no magic pill. you didn't get this way over night and you won't get better over night.
your academic achievements are outstanding and you should be very proud. now, if possible find a good inpatient program for your eating disorder so you can enjoy life. wish you the best of luck