Don't think about just hopping on the wagon. Hop in the driver's seat
Veggies and some fruit are good. I encourage you to eat them. (Hint: butter) But some people here do just eat meat and fat.
Working out is great. But staying active is most important, like doing a brisk walk every day or something. But 80% of primal is diet.
What made a huge difference for me was intermittent fasting - Just skipping some meals.
For sure stay on the CPAP. I refuse to take meds but I am not suggesting you do that. You just need to keep working basic primal. Go through Mark's 10 points to make sure you are doing them.