Dream or a Nocturnal Emission?

So I had a dream where I was masturbating and I suddenly wake up and feel like I was finishing . I was waking so I wasn't all conscious. But the thing is, I check my pants and THERE IS NOTHING THERE. What's up with that? No stains on my shorts or my white briefs. Perhaps I came only a small amount so that it cannot be seen at all? And like I thought 5 minutes before I saw a few stains on my shorts. But if that was true, then there should have been something on my underwear. So do you think that was a dream or a real Nocturnal Emission?