*I need to work on myself. When I am most depressed I want to work a spell that is harmful*
Not to sound harsh here *sorry* but why would you want to do a harmful spell because *YOU* yourself are not happy? sounds a bit like being selfish and wanting to do harm to others for the sake of it..
Or is it the fact you want to do harm to yourself using magick?
Either way i suggest you take a look at why your depressed, what triggers your depression..and how you can change this situation. There are herbal remedies that can help with depression. Meditation and calming yourself and mind helps also.
If however this has been a long term occurrence maybe seeking some professional.
Depression is a hard thing to deal with trust me I know, But with help and support from other people you can beat this, but you also have to be able to help yourself and want to.
Good luck and many blessings.