No YANBU to be devastated but depends on why really!! 
I had a friend over to watch it together - her mum has cancer atm and started chemo christmas eve eve and I had to say goodbye to my nan-in-law (very close to her) as she died from terminal cancer. She dies 5 hours after the family met to say goodbye. 
So yes we both sobbed shed a few tears but more due to RL than the fact we won't have 'Pat' on our screens again.
Oh and we did get a grip after and had a good few hours laughter! 