Nightmares?

My son will be 1 in two weeks. The past 2 nights he has woke up SCREAMING and I mean screaming bloody murder, kicking his legs and when I went to get him his eyes were still halfway shut and he wouldn’t hold his head up like he was still asleep. I held him and tried rocking him and he didn’t want any part of it. I gave him his paci and his elephant blankie thing he’s attached to and he shut his eyes and acted like he had been asleep the whole time. I laid him back in bed and he slept all through the night. I was so confused and so scared the first time it happened and now I’m really concerned since it’s happened a second time. Any advice or help?????