Nursery heartbreak

I 100% knew it was going to be hard going back to work and settling into nursery but my toddler has just finished his 3rd settle session (Tuesday night was his first night away from us, he stayed with his grandma because I had a shift at 5am) and literally had a breakdown, a fit almost, his body was tensed up and completely consumed by his hurt, heartbreak or whatever trauma he’s feeling 💔 What on earth do I do? How do I prevent this from happening or give him reassurance? It’s still near impossible to communicate. I feel like a failure