Don't worry, you're definitely not the only one.
The show's been a part of my life for seven years now. Through this time, my own life has been through some serious changes and downers. BtVS has always been a friend through the hard times and a reminder of the good times.
Now that it's over, I'm left with an empty feeling.
I still hold hope that there will be some spark later, either a film or a new season, then end is too open-ended for me to let it rest. Maybe that's just hope talking though.