Fatigue and depression

Hi all, I'm new here, I can tell my whole long sad story sometime but right now I was just curious about people's experience with fatigue... I know depression can cause fatigue of course, but this seems like more.

It started after my first child was born 5 years ago... just constant fatigue everyday... naturally at first I thought it was just adjusting to motherhood, but even when she started sleeping through the night and I was getting 8 hours every night, I still woke up exhausted.

Since then I've explored about every option, tons of blood work, including thyroid, vitamin D, B, iron, all the common causes... all normal. I've seen doctors, naturopaths, everyone... I even found out I had mild sleep apnea, but the cpap, despite "working", didn't help the fatigue.

It's the heart of all my problems... I'm just too tired to do anything, and I have to take care of my 5 and 2 year old every morning, it's more than I can take, all I want to do is sleep

Has anyone had such crippling fatigue? Find out anything about it? Could it really just be the depression? Or any ideas on what else I can try?? So tired of being so tired