Is it normal i can't get a job because of my tiredness?

I've always been overly tired throughout my life, and it's getting worse. When I sleep I go out cold, literally nothing can wake me up unless someone yells at me for 5 minutes. I sleep around 14 hours a day, and can only get up when my body lets me. When I do finally wake up I still feel tired, and only after a few hours I get lethargic and feel like I'm going to pass out.

Because of this I can't get a job, I've struggled through school and nearly always took a two or three days off every week, I know if I did get a job they'd fire me if I took to many days off. I can usually only work for a few hours, otherwise I get very tired quickly and become very bad.

I know some people might just write it off as laziness, and some people in my life really do think I'm just lazy, but I really do want to wake up. I've missed meetings and social gatherings because of this, when I go to sleep I set an alarm or tell someone to wake me up, but I always sleep through everything and I hate it!

I went to the doctor a few months ago and they said I have thyroid problems and low protein and he gave me multi-vitamin tablets but they aren't working. I also eat quite healthy, I eat fruit and veges but I'll admit I don't eat much beef for protein though.

I can usually go outside such as like for exercise or to the shops once, but after this I need to rest for around 3 days because of how tired it makes me.

I've already had a couple of blood tests and other tests done but nothing other than the thyroid and low protein has come up. I hate this and I just want to die because I feel useless at not being able to work for my own money or do anything for society