I want to sympathize with you too, your parents and your dog love YOU not your job, or ups and downs.
YOU are not your job, and you are not mistakes you've made. As long as you have life in you, you are allowed to make mistakes and to try to find a job and things that suit you.
When my son goes through depression he sounds a lot like you, everything is all joined together.
That's just your brain making connections with all sorts of things from your entire life, the brain is an amazing computer and the chemistry in your body told it to do what it's doing now.
This is what antidepressant medicine is for, helping all of that to get in balance.
Talking to a counselor can help make sense of it all too.
I hope you have access to those things.
You'll be ok.