1) ALL rescue organizations need to say NO sometimes.
2) If all you can help is 1 animal, you've done good. So you need have NO guilt FOR THOSE YOU need TO TURN AWAY.
3) Going into debt over your head will not help anyone.
4) You can not save the world.
5) Charge a set adoption fee even for those animals that have not cost you that much (because the next animal might cost more) The idea is to have it even out in the end.
6) Ask for a drop-off fee. If a person wants to relinquish their cat badly enough, they can make a donation towards its care. (Our local SPCA charges for drop-off)
7) The more animals that pass through your doors the greater chance that you will encounter deaths. This is a fact of life.
8) Find other people also interested in rescue and start up an organization that can possibly one day be turned into a full-fledged non-profit organization that can then start doing fund-raising etc. ALL groups start with one person.
9) An most importantly know this:

YOU'VE DONE GREAT THINGS AND WE ARE ALL PROUD OF YOU !!!