What changed

I started this morning with a feeling of finally things are turning around. I felt like I could take on the world, I felt like I had found that little piece of me thats been eluding me for so long and I had realised that it was time to let go and to move forward. That I was finally where I wanted to be and on the right track. And yet now not even 6 hours later here I am feeling like the lowest piece of worthlessness on the planet. I don't know why, I can't describe it. It's like my bubble has burst, like I just want to disappear. I just want it all to be over. The humiliation, the self doubt, the recriminations and most of all the pain. I cant understand it, it's like a switch was tripped and now I just don't want to be. It's like the hope is gone...........