Going strict paleo eliminated 95% of my "ADHD". By that, I mean "severe brain fog and inability to concentrate". It took about 3 months of eating completely clean with no to minimally processed foods. I also discovered/was diagnosed celiac as well.
All I can tell you about cooking is to get used to it. Ease yourself into the lifestyle like one meal a day for a week, then build up from there. I have times where I don't cook and I grab something trashy like a Larabar or some plain pork rinds (which really aren't all that trashy). I work an insane amount of the time and a travel extensively so am I perfect? No, but I do the best I can. My suggestion is to cook in bulk and then you'll have food for several days. Cooking something like a roast is easy and it lasts a really long time. Toss crap into a crock pot, come back 8 hours later, enjoy.
Grill/Bake several lbs of chicken breasts at once, make a huge batch of tuna salad, etc. A lot of my meals are relatively simple. A lot of times I'll get a wok and toss in 2 or 3 types of greens, squash, chicken/steak and saute it all with olive oil and my own homemade cajun seasoning. It doesn't take long and my girlfriend loves it. I can make a large amount and then split it up in tupperware and keep half and give half to her to take home for lunches the rest of the week.
You're just going to have to change your mindset from, "I'm hungry, I wonder what there is to eat" to "I know I'm gonna be hungry, I better go ahead and plan my week out". I personally don't plan my whole week out for each meal, but some people find it helpful to do so, especially those that haven't been big cookers in the past. Just stock up on a bunch of different seasonings and dive in. One of my favorite meals is scrambled eggs and sausage with a massive mix of herbs and spices. You'll find what you like and eventually you'll discover a couple of easy/fast "go to" meals that don't take long at all.