I am sorry to hear that!
I would agree it is possible they changed formula a little - it is possible your body chemistry changed. If it has been some time since you owned and used it last it is possible your memory of the scent isn't perfect (scent memories aren't perfect either - though they are a whole lot better than other sensory memories! I only say this because I loved Joop in college, and when I had a chance to try it again - I really hated it and it smelled nothing like I remembered).
Well ... bummer!