I have been feeling very depressed and it hasn’t gone away?

Hello my name is (…) and I am worried about my Health,since the beginning of this year I have been feeling very depressed and it hasn’t gone away I tried to talk to several people about it and they all said I should talk to a doctor .i have been struggling to sleep and when I do I over sleep,I can’t continue with my hobbies because I haven’t had the energy to do anything and it’s distracting me from completing my work,I have slowly started to experience theses problems more than usual and it has gotten to a point I am withdrawing from family and friends I would like to know why I feel this way or what this might be

​your opinion is much appreciated