I agree. Get a lot of information and keep track of your episodes. Even after seeing my sleep dr., I was realizing I had done things before that I had totally forgotten about. For instance, one of the questions was if you have ever woken up short of breath or gasping for a breath. I said no. Then a few days later I was thinking about it and realized I wake up choking and coughing and it feels like my throat is glued shut and I can't breathe. Also a very scary feeling. Like you, I only had a few of these episodes, and you kind of just brush them off. It wasn't like it was happening all the time, so you dismiss it. Not to mention that I would usually just go right back to sleep again not thinking that much about it. I also never thought I snored, but my husband and daughter in the past year have said I did. I thought they were just teasing me. Guess what? The study showed 2 out of a 4 scale for snoring! Guess it is hard not to believe that! I went to bed exhausted, woke up exhausted and spent my day exhausted despite getting 8-10 hours of (what I now know was horrible quality) sleep. I believe, and I may be wrong, that generally if you have OSA you are tired during the day. But what about Central Sleep Apnea? Anyone have anything to add about that which may help?
One reason that it may seem like a dream is that you are probably in a deeper sleep (that is when your throat relaxes the most and most people have the most apneas) and may actually be in a dream state (REM). I know when I am woken up suddenly from a deep sleep it is a very strange feeling. Disoriented and sleepy and confused is how I feel. I can understand being confused between a dream and reality.
My sleep dr. had me fill out a quesionaire, and then sent me home with an overnight oximeter. Because I showed to have lowered oxygen levels while sleeping, which can indicate apnea, I had the overnight study at the sleep center. The study itself is really no big deal, I found it kind of interesting. It is very expensive though, and you would hope to have insurance pay for it, as I just got the bill and it was $4000. I can say that on here right??

The overnight oximeter was $200. I am guessing that if I didn't have the lowered oxygen levels, she wouldn't have ordered the sleep study. I am glad I had it though.
Good luck, I hope you can figure out what is going on!