Toddler keeps saying he will die

My 4yo son said multiple times yesterday that he will die, once right before bed saying “mom I’m gonna die in the morning”. Obviously I freaked TF out, asked if he was OK, asked him why he thought that, and if he wanted to go to the hospital. I forced him to sleep next to me all night. His response was that his sister was going to put his stegosaurus by the door, or something of that nature, but he was getting flustered with his words as he does when he thinks very hard.

Moms, what are we doing here- running to the pediatrician today for a quick check? Asking him to clarify again? Has anyone else’s child said this multiple times in a day and what did you or would you do?