Ignore the "just get on with it" brigade. Not helpful at all. What you need to do it prioritise yourself and be kind to yourself. I've suffered with depression in the past and you need to treat it as the illness it is. Would you feel the same if you had, say, diabetes or high blood pressure and feel the same sense of failure? Anyone can succumb to depression and it is NOT a weakness, whatever anyone says to you.
There is light at the end of the tunnel, believe me. As Smileless says, the effects of anti-depressants are not instant but please hang in there and take all the help you can get, short term and long term.
Sending you my very best wishes and a virtual hug.