Sleep Apnea Treatment

I started experiencing this weird thing, of what I believe is a sleep disorder, about 3yrs ago. Its kind of hard to explain, but I am going to do my best. My problem is that when I lay down, and began to fall asleep, i suddenly wake up startled. Sometimes it can go on for a few minutes, until I am finally able to go to sleep. I went to the ER about it awhile back, and was told by the ER doc, that I need to stop drinking soda so much. Back then, I was drinking about 5-10 pepsi’s a day. Now I am done to about 1-2 a week, and I now it rarely happens. But now when it happens I cant help but worry about my health. Is this a sleep disorder, or something else?