Depression

I keep seeing a dog on my sofa but I can’t tell which one it is
I’ve had a few puppies before and every one of them died
I keep seeing things from the corner of my eye but they just fly past
What does it mean? Why do they come back?

I re-live what I have lived, I see it as I ride down the road
I am careful, I check each corner before I pass
Only one mishap. I saw that again tonight
Why am I running? Is this it flashing before my eyes?

I can’t live them again, they were not what I wanted then
I wish I could though.