Night Terrors?

My son is 6 months old. he has been waking up in the middle of the night for the last couple of months screaming like hes being killed. When i flip the light on, he wakes up, blinks at me and then crys to be picked up. after that he is fine and goes back to sleep. i dont think its gas because he doesnt needgas drop or anything else ike that to make the screaming stop- just turning the light on. i kd a nurse about it and she sai she had never heard of it, it must be gas,,,,what do u think