Sudden bedtime troubles

I need HELP!! My son (turning two on the 25th) suddenly HATES going to bed. I am not sure what the issue is. He usually is totally fine runs into his bed and will eventually fall asleep on his own no problem. The past three nights it's been a struggle to say the least. He screams and screams and screams. Will not go in his bed and stays at the door. I'm at a loss and exhausted. And he will even wake up in the middle of the night and start screaming as well and will not go back to sleep. Anyone else dealing with this?