I have been there myself fairly recently so I know where you are coming from. I think circumstances in life can change the way you feel about yourself more than one realises. For some stupid reason I find it easier to possibly help someone else when they are down, even if I may be in the depths of despair. So I would suggest that you talk to other people on here who may or may not have been through some form of depression and get some feedback from them. Seems to work for me talking to people who know nothing about me, therefore no preconceptions as to who I am .
Books are great. Louise Hayes has some useful ones.
You may heading towards a turning point in your life,there are many self help good books out there,I have read many and passed them on,many times I ask the guestion,Oh God,where am I at in this world?The best to you!
Easy....Remember the last time you felt that you loved yourself.
Then look as what has changed........There you will find your answer.
You're changing. Never-ending process.