E.I.
sounds like my son!
he did the same thing when he was just a few months old too. he did it quite a few times.
i want you to know first of all, that its great that you went to him to comfort him! even if hes not awake, even if he wont remember it in the morning, it is a great idea to go to him and hold him and try to calm him. this not only can help him, it can help YOU. :D this is important! :D
anyway, i had night terrors as a child, and my son has had them too. its just something we have to deal with. the only thing that ive heard helps is to figure out how long after falling asleep this happens, and try to wake them before it happens. another thing i JUST heard about is to do a nighttime routine that includes snuggling and singing a song or something and sorta pretending to wrap baby in a blanket of security and love. help them to relax. that way when they wake scared and screaming, you can go through that same routine again, snuggling, and wrapping them in that blanket of security, and i guess its sposed to help. i havent tried it as its been a while since my son has had a terror.
anway, prepare yourself to have more of these. its unknown why or how they happen, or when the next one will be. try to keep your child from being unnecessarily scared by tv or movies or something, and you know... just love him! :D
:D
trust yourself, only you know the needs of your child! :D