Hey there, Tina. I'm a 24 male, and while I cant relate to you for the husband/wife/significant other, and child thing, I can relate to your impulses and thoughts while depressed. I feel very similar things when I'm depressed; including the self harm ideas. I have even thought and came close to am attempt on my life.
Anyhoo. You should seek professional help if you have not yet already. Medication, if you're patient in finding the right combo, is, and can be, a huge weight lift in your daily life. I encourage you to seek professional help in the form of a Therapist and a Psychiatrist.
So, in short, welcome to the forum.