Hi,
I am sad to hear your Oscar is not well and wish him speedy recovery to allow you to rest.
Do not give yourself a hard time you care a lot for fish and perhaps someone may help you with your fish especially as your back is bad.
Look after No1 though ensure your seen by the Dr. and getting the correct treatment for yourself which will not mean lifting heavy buckets etc.
Have you a python and could someone else vaccum the tank? Invest in easier ways and I hope you do not lose them.
I wish I could help.
Thinking of you.