I think I know what you're talking about, though I'm not sure what the "tuning head side" of the bass means...
You were changing your strings, your bridge saddle fell out, and now that you've put it back in, you're noticing a buzz, yes?
Well, I won't say these two things are unrelated, but they're definitely not SUPPOSED to be...
My honest guess is that the saddle has nothing to do with this. I wonder, did you take ALL the strings off your bass at the same time when changing strings? Sometimes this can put relief into the neck that STAYS THERE even after you put the strings back on, and it can mess with the way your bass was set up before you re-strung it.
So, I'd suggest getting that bridge saddle back down to a "normal" height, and then head over to the "Tips And Tricks" section to read the posts about how to set up your bass... I talk about adjusting the truss rod and the nut in the post marked "Your Rod And Your Nuts", and there have been a lot of other great contributions to the thread.
Check it out, and then if you have any questions, feel free to ask!