What a pickle for you
@Ale. I can quite understand how you got into it, though. I'd like to be generous and assume that Brodie's owner just hasn't;t thought through the implications for you, rather than that she is taking advantage of you. I hope that if you start with an open conversation, "I need to look at my financial and time commitments and how they are working out for me, you know I adore Brodie but things seem a bit skewed at present," she may offer some concession which will make things fairer from your perspective. If not, well, you can ask her politely to make a contribution to your pet sitting. Good pet sitters are gold dust, she will not want to lose you!