What is wrong with me?

I cry nearly every night, my sleeping and eating habits have recently changed rapidly. I feel guilty, worthless, hopeless and that there is nothing left for me. I’m always nice to people and feel they mistake my kindness for weakness. I have my best friends but i can’t talk to them about this. When i wake up i can barely find the will or energy to get out of bed or to eat. I don’t want to do anything, everything that i was interested in before seems pointless and uninteresting and i just really don’t know what to think anymore, or what to do with myself, I don’t think it’s depression because when i have tried to talk to mum i mentioned it and she just laughed at me and said i was overeacting. I do everything very slowly as i just can’t be bothered instead of going out and haveing fun like i used to i just want to lay in my bed and listen to songs like everything by lifehouse, possibilities by lykke Li and songs like that, whereas i used to be into drum and bass and dubstep! DRAMATIC CHANGE!!! What the fuck is wrong with me?