That’s a tough thing to have to deal with. Spaceyness is indeed the hallmark of inattentive ADHD (and don’t I intimately know it!), but it can be aggravated by multiple factors, such as stress and physical health problems. However, when we are interested in something, the hyperfocus kicks in and it’s suddenly easy. Do you have a hobby where you can concentrate for hours? If yes, it’s ADHD. If no, then I think it’s time to look for physical health issues, because if mental health was the only issue, all these psychiatrists would have done something to help.
Two issues my family has personal knowledge of are asthma and sleep apnea, both of which could create the sort of symptoms you are describing. If you snore or have sleep disturbances, have a sleep test. If you react strongly to perfumes or smoke, cough for no reason, wheeze, or yawn as if gasping, check for asthma. The asthma was diagnosed for many years as anxiety disorder, and often led to obsessive thoughts — it was so odd to see all that disappear with a puff of the inhaler! ADHD people are all too primed to blame their mind, when in fact mind and body always go together.
Something else to check is whatever medication you are being prescribed. Unfortunately, many people taking antidepressants for long term report decreases in focus, memory retrieval, overall motivation, and the emotions (both good and bad) have dampened which makes it hard to feel joy about anything. Often anti-anxiety and anti-psychotic medication is added to control the side-effects, and the resulting cocktail can be very damaging even after the medicines are stopped. Doctors often have no idea how to handle this, since there are so many different individual reactions. Do not cut any medicine cold turkey!!! Take a look at SurvivingAntidepressants.org to see if anything rings a bell.