According to india yoga , there are 3 relaxations to need to a human being,
1. physical relaxation
2. mental relaxation
3. spiritual relaxation
If you are still fatigue even if you took a rest and slept last night,
maybe you only take a physical relaxation, but you don't care
You always want to sleep, but your brain don't stop , so you couldn't sleep well.
But it's not easy to take a mental relaxation
You just need cozy bed and blanket if you want a physical relaxation,
but I have to say about mental relaxation, you need more than that.
besides, in spite of all your efforts, maybe it could be beyond you.
so it's very difficult, but never give up and hold on to your hope.
You can overcome all your difficulties to practice yoga asana
But if you won't be able to afford to go to a yoga class,
you can practice it at home or just listen to yoga, meditation or classical music.