First, you gotta find out where the anger and depression are coming from. Even if you don't necessarily feel it right now, if it's lingering/hiding... find it, and address it. Think about why those feelings exist for you, think about what you learned from experiencing those feelings, and release them. Forgive those who you feel helped create those emotions.
I know one of the reasons we experience anything negative is that so we can relate to others. It's more like a bonus of experiencing those emotions, going through something and persevering and then being able to relate to someone else going through a similar situation and helping if they seek the help.
Another reason we experience negativity, is to know how to recognize it, and compare it to it's polar opposite. Gotta know sadness to fully appreciate happiness.
I recommend clicking on the link in my signature if you feel you are still stuck.