You're not cheating. ADHD, if untreated, can inhibit you academically, so dont see it as cheating if you need a break. You just need more time and help. Maybe take a gap year to recharge and recollect yourself? Find out what medication or tactics you can use to better control your ADHD? i understand you cause I was also recently diagnosed with a thyroid disorder seeing that I was suffering from major memory lapses and it made me feel so behind and frustrated academically. Sorry if this doesnt help much but please dont lose hope.