There are two things you need to know for this story to make sense. The first is that Maisy loves toys. I'll attach a picture of her because it's cute and hopefully it will illustrate my point.
Maisy loves her toys so much that a game of fetch is more regularly a game of keep-away, with her being the one keeping away. She'd have the ball (or rope, etc) and she'll hold it in her mouth near you, but if you try to reach for it, she'll back off or run away or let you play tug-of-war even though it's just a tennis ball, but she won't let you have it.
The second thing to know is that I was sad on Monday night. It doesn't quite matter why I was sad, it's just a part of the story.
I go to bed feeling sad and expect that to be the end of my night. I'll be in bed for a while, thinking, but pretty much any notable thing that would have happened already did.
Except that Maisy hopped up on the bed before I fell asleep, her tennis ball in her mouth. She walked over to me and very carefully set the ball right on my chest, then she curled up next to me and just watched me.
It's probably dumb to ascribe human emotions to dogs, but I swear it felt like she was thinking "This makes me happy. Maybe if I give it to you, it will make you happy."
So that's how I fell asleep. A dog curled up next to me and her tennis ball on my chest.