Unity all objects gone?

Yesterday, I created a few capsules and the code for them in Unity. I saved them and was just about to call them.

But now there's not a single object left? The entire hierarchy is empty. And it's like this every time. The script I wrote is still there, as are the materials, but I don't want to recreate the entire scene every time, only for it to be gone the next time? How do I save this correctly, or where are my objects? There isn't a single video about it.