Believe me, I have met many people who are far more "handicapped" than you, and they lead perfectly fulfilling lives.
Although study might be a bit more challenging, that just means you're going to have work a little bit harder for what you want most in life. And that's going to make it worth so much more!
"mental funk." I discovered that the root of the problem was actually a sort of anxiety. The trick to overcoming most of it is to simply stop dwelling on it. If you really think your brain is damaged, there are more than enough articles out there explaining the various ways the brain is able to repair itself over time. Almost everyone that complains about mental impairment improves over time--yes it's true, sometimes this can take a couple of years [...] None of us made you take those pills, after all.
Firstly, what trip says is true: people from all walks of life encounter tremendous adversity and yet some persevere. Separating those that do from those that don't is a little personal factor affectionately known as 'determination' or 'will power'. Depression and anxiety stifle determination. You may be cognitively affected by MDMA but you don't have to be emotionally affected.
Second: studying, if indeed you are experiencing genuine cognitive dysfunction, will undoubtedly be more difficult. But you know this, yet you haven't changed your approach to studying. 'Chunking', as it's commonly referred to as, has proven to be a less effective studying strategy for the majority of the population; simply put, there are other, more potent studying and memorization techniques that significantly improve comprehension and memory retention--look into these. I'm a bit surprised to hear that a field-leading neurologist 1) facepalmed you (not only is this personally devastating but also incredibly detrimental to neurological recovery), 2) didn't recommend a language therapist, or psychologist, and 3) failed to provide any conclusive physical evidence of cognitive impairment. I mention this only because these are serious overlooked medical measures--this neurologist, while he may be at the top of his field in some particular speciality in neurology, may not have the extensive background necessary to treat your case. You might seriously consider another neurologist, especially one open to various alternative therapies and one willing to provide a more holistic treatment regimen.
Third: It's interesting just how pervasive and severe the effect of acute and chronic anxiety is. I myself know this well and can attest to many of the same cognitive difficulties you've been facing. Do note, I'm not trying to reduce you're apparent troubles to anxiety, but they are a factor and merit some weight. Reduce anxiety and depression, improve mood in the short-term and extensiveness of recovery in the long-term (mood serves as a critical element mediating neurotrophic environment; a supportive neurotrophic environment assists in regrowth and ameliorates current deficit). The brain does possess the inherent capacity to build upon itself in both a healthy and injured brain. Actually, in an injured brain, the regenerative processes are in a sense intensified (neuroplasticity/neurogenesis induced by brain injury in cases ranging from cerebral ischemia [stroke] to traumatic concussion to neurotoxicity from various substances, conditions, and environments). Neuronal generation in the healthy brain is more restricted, usually constrained to forming new memories. For example, while in a normal, healthy brain we see no evidence of axonal generation in the neocortex (an area responsible for higher executive functions), we do see it after brain insult, e.g., MDMA neurotoxicity in squirrel monkeys was more extensive at 18 months than after 6 months and after 7 years than at 18 months. While regeneration was not complete after 7 years, it was more complete and in large part entirely unassisted by any kind of regenerative therapy (no psychotherapy, no medication, no specifically supportive diet).
As I read your case I'm reminded of a study I read not too long ago, "Hippocampal remodelling after MDMA neurotoxicity: A single case study". The authors note, "Recent studies demonstrated that MDMA induces damage of serotonergic nerve terminals and alters hippocampal processing. Pronounced cognitive deficits in MDMA users affect learning and memory abilities [...] After 16 months of intensive neuropsychological rehabilitation she showed significant improvement in hippocampal-related memory cognitive functions, which correlated with normalization of her 18F-FDG-PET and remarkable hippocampal remodelling. This case report indicates that even non-chronic MDMA use may cause subacute toxic encephalopathy in which the clinical evolution is paralleled by neuroimaging changes in specific cerebral areas. The most relevant aspect is the reversibility of the volumetric changes, which may be the structural correlate of an ongoing hippocampal remodelling." (Nifosi, 2009). 3 months of studying seems hardly adequate for the change you're looking for... Additionally, in the vast majority of anecdotal reports the dysfunction becomes more tolerable not only because of an improvement in individual coping, but also a perceived reduction in cognitive deficits: a recent study on methamphetamine reports that an improvement in global executive function became apparent at 2 years after abstinence, but no such evidence was demonstrated at 6 months post-meth. Most significant to me is that one of the measures of recovery--performance on the RAVLT (a neuropsychological verbal learning test)--improved after 2 years but in other forms of brain injury, recovery of this particular function typically ceases after 6 months.
In all, the reasoning could extend for quite a long time. Most important is that you truly recognize the debilitating shortcomings of your current conceptual methodology, the established potential for structural and functional recovery after brain insult, and your own role in that recovery. I'm not attempting to pamper you, I'm not trying to comfort you, I'm correcting you. And I could give a damn about the promotion of MDMA; what I do care about is intellectual integrity and preserving, or in your case--resurrecting--human dignity. You are pathetic and you don't me need to tell you that for you to be well aware of it, but you don't have to be.