My 4 year old came into my room 2 days ago at 1am scared and crying telling me he had a bad dream that I forgot him at…

My 4 year old came into my room 2 days ago at 1am scared and crying telling me he had a bad dream that I forgot him at school 😕 which is weird cos I’m never late to pick him up from Pre-K. Then yesterday he randomly walked up to me while I was making dinner and was crying. But I mean really crying. Like if his dog got ran over or something crying. So I asked what’s wrong and he said “I don’t want you to leave” but I told him I didn’t have to go out today so I wasn’t leaving. Then he said “if you leave you’ll never come back” and I was so confused cos I always come back anytime I have to run an errand. Then he said “if you leave I’ll never see you again cos you’ll walk into the forest and something will bite you and you’ll die”. And I kept reassuring him that mommy always comes back after running errands. I finally got him to calm down letting him know I would never abandon him. But I’m just so confused. He has never EVER been scared or worried about me going to run errands. I’m not sure if he saw something scary on his iPad, or maybe another little kid at school told him his mother left him? Or maybe something happen at school and is being threaten with “if you tell your mom she’ll leave forever”. Have any of your toddlers randomly thought y’all were gonna abandon them?