I think it's actually melatonin that effects your sleep.....serotonin affects your appetite....and mood... i believe....not 100% but i think...lol...sorry to pick

but anway, I've had that happen to me a couple of times before...but just assumed that i've still been dreaming when i woke up...waking up from a dream and still being in a dream is weird....
I didnt know it was called night terrors though...thats some mental shit...