Buddhism and depression/suicide

This one I have to think about.  I've read of cases where Buddha approved of the suicide of someone who was no longer wanting anything samsara had to offer and was ready to move on to becoming a Buddha, then consider the buddhist monks who have killed themselves for what they believed was a greater cause/ self-sacraficing.  Me, I loose my attachment to all of this easily.  But that seems to happen when I am very unhappy about the lack of control over my own life, my own destination,  i was really angry before, and my anger, when I'm feeling helpless quickly turns to depression and so it goes until I come down to this.  the goal of Buddhism is to become so unattached to this body and this life that your spirit never returns, and what is the ultimate example of that but when one dies to get away from it, to renounce it? To leave it and say this shithole no longer has anything I desire to have, and never follows through with any promises, and only continues to offer up one suffering day after another and I am done with it.