Fellow anorexic “athlete” here.
What you are describing is quite normal. Given how low your BMI got, and your height, I think it will take a tremendous amount of caloric energy to get you out. I’m not even basing that on what I’ve read here so much as what I’ve seen of other guys in treatment-especially guys in their teens and 20s. I don’t know how old you are.
What you are describing sounds like symptoms of energy deficits. So you maybe got yourself out of deficit for a very short time, felt better, but then started exercising again and bam! no more happy symptoms.
Can you be sedentary for a while? You have a ways to go in terms of weight gain an calories above basic metabolic need to get to where you likely need to be for your body (and subsequently, your mind) to find peace.
As far as hungry all the time, yes, well, that makes sense-you starved yourself enough to get down to a very emaciated weight…so when your body realized food was going to be part of the deal again it got happy and is now sending you a very healthy signal-EAT!
For me, the brain fog, depression, anxiety, and irritability do not go away if I just up the cals. I have to get off the exercise. I’ve played around with this several times. Every time I start the sports again (running is my thing) I fall back into that mental trap. I’m not swearing off running forever, but for now it isn’t worth the mental prison it causes. I really think if my body is allowed to fully recover, that some day I’ll be able to run without all the rules and rigidity and compulsion. But it’s gonna take some time. It also means I need to just relax. For me, some of the stuff on this forum about refined sugar vs unrefined, or carb to fat ratios, and blah blah blah, are just not healthy indulgences. Orthorexia is a bitch. I don’t want that any more than I want anorexia.
Anyway, what you’re experiencing is normal. You can proceed with the expectation that it will be uncomfortable, will rock your world, and will force you to challenge your beliefs, perceptions, coping skills, and perspective on life in general. Or you can go back to the hell you came from. You didn’t say it was hell, but it sounds that way so I’m assuming.