bag seed grow went down the drain??

I checked up on my grow today to see that the plant has gotten so big the lights are burning them. So I cut the plant about 2 nodes down and I thought I should try to clone it. When I cut it and put the rooting stuff on it. I cut the big leaves and after I did all that I left it alone for about an hour and when I went back that part of the plant wasnt standing it was over the side. Did I kill it?
I still have 2 clones and the other half of the plant growing as well.

anyhelp???