Can I say no to in-laws wanting me to work?

My partner’s family has been dropping hints since day one that I should get a job. Not the ‘oh it’s good for you’ kind, more like ‘how come you not working?’ every time we visit. Thing is, I’m already managing her parents’ medical appointments, helping with their bills, cooking when they’re over — all without pay. And I’m not even in a full-time job because my own family needs me too. Last week her brother outright said, ‘You earn nothing, how you support family?’ Aiyah, I felt so small. I told my partner I can’t take on another job right now, but he just said ‘just find something part-time, can or not?’ Like it’s that easy. I know in our culture, two incomes help, but what about everything else I’m doing? Is it wrong to ask that my effort count for something? Walao, sometimes I wonder if they see me as a liability instead of part of the family.