Struggling with Depression and Self-Identity

soo.. I guess I've fallen back into depression.. I've been trying to fight it or maybe I was just in denial. I can't seem to pull myself together. I've had a 3rd child and I guess my hormones have gotten the best of me again. I don't recognize myself but I can't remember who I was to even know where to start to get myself back.. my self identity, my self worth, my self image are so wrapped up in my messed up childhood, my husband and my kids that I don't even know who I am or what I like.. I can't even make simple decisions for myself. I don't know where to begin to start putting myself first without feeling like I'm letting everyone else down.