That's sad to hear. At least you can learn from these experiences. But i've had the same experience, when my fish have died i've cried as well. So your not the only one at all.
I always attempt to salvage some old media. Just to be safeOP....When you say you change out the media in your filter, do you throw part of it away? All of it away?
Do you replace it with out of the box new media?
do you squeeze out some used media in old tank water, and replace it?
Good to see, I never throw any filter media away until it falls apart, your media is your life support for the tank.I always attempt to salvage some old media. Just to be safe