hi BlueCrustacean

That your moods go up and down like that might suggest that you need a mood stabilizer to regulate them. The doctor should be able to advise about that. But that you come up again after being down is reassuring because then you know the bad periods will not last.
When things go wrong, like the dogs marking the floor. It is important to remember that this is just one thing gone wrong, and that you have got a lot of other things right, which helps you to keep things in a balance perspective to help with your self-esteem. Also making a list of all the things you achieve and reading it when you are tempted to feel bad about yourself will help to counteract this feeling.
Don't worry about the suicidal thoughts. They are just thoughts and can't make us do anything as we are in charge of what they do. Getting a lot of stuff done should make you feel good as you are achieving well. I hope and pray you have a really great day. God bless and best wishes from your friend Francis