This is how I handled my feelings of utter worthlessness.
I've kept a personal journal for many years.
One day maybe 6 or 7 years ago I decided to try making a list of the good things about myself on the pages of the journal.
That first time, the only thing I could think of was that some people had told me that I have a nice smile. I was crying as I wrote that down, because I couldn't think of anything else.
But after a day or two, I tried again. And I thought of other things. And I wrote every now and then and added to the list.
Within a year I had collected plenty of things to feel good about, and they were convincing, because I was doing the telling instead of relying on the words of others. It helped me develop a sense that I was better than I'd thought I was, and this has stayed with me.
Of course four years of being unemployed has done damage, but I still have that feeling that deep down inside I'm worth something.