Who taught you that you don’t deserve happiness, baby? Who wounded you that way? Addiction, depression–these things are chemical. Overcoming them is difficult and sometimes we return to familiar patterns because we’re hurting. You don’t turn to them because you’re a bad person, you turn to them because you don’t know what else to do. Please seek help, sweetheart. Find a professional who can ease you through this.
And be gentle with yourself. Because you, without a doubt, deserve to be happy.