Why am I so tired?

I am tired all the time. It doesn’t matter how much sleep I get. I am always tired. The thing is though, I have to take melatonin to even fall asleep at night. Otherwise my body will fight sleep. I am just so tired of being tired! I’ve changed my eating habits. Actually lost a bunch of weight. I try to workout everyday if not its every other day. I can’t get motivated. Which isn’t good since I am on my last year of college and I’ll sit here, thinking “I need to get this work turned in” and not do it. Because mentally and physically I’m just too tired to focus. What is going on? I have been diagnosed with depression and anxiety. Though I don’t think that’s it. Also vertigo. But also unsure if that is it. I’ve gotten tons of blood work to rule out different things. (When being diagnosed with my vertigo) I’m just curious as to what could be going on.

Not my thyroid. I’ve had that checked.