Tiredness a year after a quad bypass

July 25 last year, I had cardiac arrest, and emergency surgery since I’d already flatlined. A few weeks later they replaced my femoral aorta. My attitude is good now, but I’m just absolutely zero energy. In fact, minus about 10 hours, I slept from Friday night until about 10:15 this morning, Monday!! I’ve tried vitamin B12 supplements, now I’m on oxygen when I sleep, which everybody assured me that I’d feel better in a day or two. Now my doctor tells my my thyroid is off a little bit (9.12) which isn’t much from normal, and even on the meds for that, I’m just totally worn out ALL the time. I’ve known a few people that have had a quad bypass, and they seem to be doin’ great. Just look at David Letterman and Regis Philbin who’s old enough to be my grandfather lol  We(me and my doctors) can’t figure this out, so ANY help or suggestions would be greatly appreciated. Thank you.btw….I eat well and prepare about 99% of my food at home, even my bread, I avoid processed foods as much as possible, and I watch what I eat as far as labeling goes. I eat LOTS of fish, mostly sardines, mackeral and cod, and I avoid sugar and caffiene, and of course I take all 13 of my meds everyday on time, or as much on time as I can, considering my strange sleep pattern.