Have you ever tried consulting with a professional? Sometimes our bodies need that extra push in order to get better and that does just not apply to our physical wellbeing but also to our mental wellbeing. If this feels too much for you, I suggest you try to reach out to families and friends as they are the ones to support you.
There is really no definitive answer. Personally, I also feel tired sometimes but I try to be grateful and look at the positive side of things. I think about the life I want to live and the people I want to live it with. I am rooting for you, mate.
There is so much to live for and I hope that you find that within you.