I have had similar problems, I gained a few unwanted pounds (10 or so) and started having the same symptoms. The doctors told me it was apnea, and suggested a few things, but ever since I lost the unwanted pounds I haven't had any problems. I suggest seeing a doctor about it as some severe cases can cause suffocation.
I have heard people say that it is sleep apnea when that happens..........you may want to see a dr. for that and have them check you for sleep apnea...........I do not know what else to do for it, wish I could help more.........take care.