Don’t give up on your CPAP machine. Once you have found the right combination, try it out for several weeks. You may see that you are less cranky, not so exhausted during the day, and you can stop using copious amounts of energy drinks.
There are those who feel the effects within a few days. For other users, it takes a longer time to feel any effects. If you have had sleep apnea for a long time, it does take a while for the CPAP machine to be efficient. There are residual effects that linger from lack of sleep, and you may need more time to pay your sleep debt back.