I'm sorry that you are dealing with all of this and hope you get some answers real soon!!!
My nanan had Progressive MS and she also suffered from Sleep Apnea. Her Neurologist decided to conduct a sleep study and found out that she would stop breathing at least 5 times an hour for quite a long time. It was so bad that in the end, she ended up having to have a CPAP machine to try and help control some of the symptoms.
I would suggest getting a sleep study if the symptoms are really bad if you haven't had one already. I hope you get some answers soon and am keeping you in my thoughts!!