My 2.5 yr old is now trying to sleep in bed with me?

He will be 3 in February. He used to sleep with us ever since i he was born but about 4-5 months ago he will sometimes go to bed in his bed other times in ours and if he sleeps in his bed the last 2 weeks ill wake up to him in our bed? Sometimes also he will scream from naps and in the middle of the night? Whats wrong?

possibly night terrors.
my son will crawl into bed with me and tell me he had bad dreams.