I know how you feel man...my bestest buddy Luke passed away a little over a year ago. He had been suffering from kidney failure for months past when they said he shoudl have been dead. The one day we made the decision that enough was enough for him...he was in such bad shape...
He passed away in the car in my arms before we ever got there...I haven't cried that hard in a long long time, but I couldn't have asked for it to end any other way.
My fiancee got my stuck on cats now...yea yea I know...but they act like dogs so its cool...but my parents got another dog and he is a total ham...completely nuts!
Here's a pic of my little man, Luke...
My advice, get another one...it doesn't replace them, but makes starting another chapter in your life alittle easier.