you don,t need to tell us about it at all,its not our business and no matter what it is wont change our desire to support you, but do you yourself know what event or events in your life caused this pain inside you? have you spoken to anyone about it, are you still speaking to anyone about it?
you aren't worthless and telling yourself that you are doesn't make it so.
I am experiencing a lot of the same feelings that you are talking about and have a similar self image to what you do, but its out of line with what other people would tell you about me and I'm sure if i were to ask those that know you about you that their views of you would totally contradict what you are saying about yourself.
During a dark patch I went through a number of years ago there was a lady that I used to see at the train station, and each morning she would flash me a friendly smile and I would smile back, and she will never know just how much I valued that smile and how much it meant to me, and for all you know you are that person in someone else's life, someone who will never know how important they are but for whom without you their day would remain dark and smile free.
I urge you to seek further medical help, a review on any medications you are taking and to talk to a psychologist or psychiatrist about what you are feeling. i would also ask that you please try challenge your self talk and when you find yourself mentally going down a dark road to stop and try create a new narrative where you recognise all that is good in you and how you are worthy of a life filled with love and happiness.