I don't know if you have tried doing this, but you should try to get professional help. I can't promise it will work, but you may get some advice on how to deal with depression or maybe some pills to fix a chemical imbalance in your brain. You should also try to do something like getting a hobby to keep you going. You may not get rid of your depression, but you might get it to a level that makes live worth living.
That being said, if you still decide to ctb and you can't really get anything, id recommend you look into hanging and more specifically partial hanging. You only need a rope or something that can work as a rope like a scarf and then an anchor point which could be a tree in a forest that nobody visits at night or one of those metal bars you might have in your closet.