Brain fog from malnutrition and other factors - what to do?

17 6 months 41-ish kg 148cm. I have been for years suffering from a form of brain fog although no medical or mental health professional I have went to took seriously that I was forgetful and couldn't process or retain information properly like I used to and it was distressing and lowering my quality of life. that was that. but then I, for some stupid reason or another, went on a disciplinary diet april 2025, which I wished to drop at around June when before that I had dizzy spills and other symptoms of malnutrition. but because I am so distracted and weighed down by other mental struggles, my eating continued to be irregular and I never got to make a full recovery as I do not get important vitamins and micronutrient, spending months without a shred of meat and eating peanut butter and starchy carbs, and so I have a mild anemia and who knows what else and I feel, ever since May when I noticed my chess insight and MATH skills somehow got ridiculously worse (CHESS is equivalent to academic performance by its correlation to g) my brain has deteriorated greatly, my performance on cognitive tasks is pronouncedly worse (Scores and whatnot), I am very slow-witted and I make uncharacteristic silly mistakes especially when following instructions, and my executive function is fucked and it's like a vicious circle or a reinforcing pernicious anomaly where, because of malnutrition, my self-control and resolve and attention, memory etc, are impaired so my alarming eating patterns are forgotten about and the bad habits continue because the idea loses its reality the next day of a breakdown over it. I cannot focus on anything or follow through with any plan I make to the point that it is SCARY. I am afraid my IQ is lower than it was before I began, now 9 months ago, which is a nightmare for me because I have obsessed over it for many years, despite what my negligent behavior might show. the diet was in essence an impulsive mistake on my part, and I fear I have caused permanent damage to myself, on top of my already messy background of a perceived mental deficiet or brain fog. I am working on improving my diet and I would definitely be eating tons of protein everyday from now on. will this compensate? any medical experts here could tell me of my prospects for full recovery of my mental capacity?

here is my blood-work: https://www.reddit.com/user/QualiaRudiment/comments/1q34gf5/cbc/