never ending nightmare

Hello I'm Rachel I've made a few posts on here anyway I have asperges syndrome and I suffer from depression. I am try to recover and when I finally start to feel happy and the depression starts to go away something always happens that brings me down again. I just feel that iI'm being punished amd that I don't deserve to be happy.  For example a few days ago my ex agreed to meet me as a friend I got really excited all set to meet him today for a coffee and to make a fresh start move on from the brake up and to start over as close friends that's all I want. Anyway this morning he texts me saying he can't make it because he has a job interview and starts his new job tomorrow. I just feel I, go into this bubble of happiness and someone comes along and bursts it. Just wanna am I we meant to be happy or are we all just living a never ending nightmare. I can't stand it anymore, I just wanna be happy again and for once can't something just go right for me or am I being punishment for, all the bad I've done.