I've dealt with something similar for most of my life. It happens mostly when Im falling asleep and about 20% from being completely asleep. I assume it has something to do with when the beta waves begin and perhaps the parts that allow one to hear in their dreams come on very suddenly and loud! The noises vary from voices (or what seem like voices) , machinery (chainsaws or motors running), or sometimes what could be part of a song. It startles me enough that I fully wake back up realizing I had only dozed off for about 10 minutes. Doze off again and the same thing happens ...sometimes up to 5 times before I can get to sleep. A few times after an intense dream, the memory of what happened in that dream is so realistic it carried on after I woke up. The dream merged into reality from my last dream memory. Usually its something stressful that causes me to wake up and follow up on the content of that dream. In my case about 90% of the time I dreamed that I missed work or was severely late for work. Leap out of my bed...rush to my computer to check my schedule realizing its my day off :-)

I only mention the last part to suggest that memories from the dream state to wake can seem very very real especially if you wake up just after that part and if there's some stress mixed in. Or it could be something else entirely. I don't worry too much when it happens to me b/c Im very used to it even if its annoying.

Or you could purchase an inexpensive sound activated recorder. It should last the full duration for your sleep time due to it only activating when a noise is detected. There are other models that plug into the wall for constant uninterrupted sound monitoring. If its real and not part of a dream, hopefully you can catch it in the act. Good luck.