Have you ever been tested for sleep apnea? This sounds an awful lot like that. I have it, and it's very disruptive. Even if you think you're sleeping a ton, you could actually be waking up all night long and not realizing it.
My sleep study showed that I was waking up 90 times per hour. But I didn't remember most of those times that all. I had no idea!
I have severe PTSD and my flashbacks mostly happen as nightmares. That was another thing that was waking me up at night or keeping me up period. I'm currently taking prazosin, which helps with the nightmares. If you are not taking that you might want to ask your doctor about it.
Two other things that I know for a fact can make you feel like you're just not getting enough sleep no matter what you do are low vitamin D and hypothyroidism.
Sometimes for vitamin D it's not enough to just take a multivitamin or something. I am on an extremely high prescription dose and I'm still deficient. I take two 50,000 IU pills a week but my level is 10 and they want it to be closer to 30.
Anyway, these are all easy to treat problems that make you feel like absolute hell and could all cause your symptoms + depression.