Am I going to be a bad mom? Or just a bad person

Long story....

I’ve been TTC for 5 years. No luck. I don’t like really kids at all (young cousins, nieces and nephews, etc) but I feel the strongest pull to be a mother- NOT just pregnant- and everyone’s told me it’s different with my own so I figured I’d try TTC.

A week ago, my mom called me home to help with my grandma having emergency surgery. She needs full care (showering, toileting, dressing, walking, opening things, everything) and my mom is in poor health too. My mom hasn’t slept in days, even after I arrived to relieve her. She refuses. Now I’m exhausted too and everything is agitating me. Doctors say my grandma needs to be more independent, but my mom keeps doing everything for her so when I relieve her I have to do it too. I’ve tried telling her “your doctor says you should do x because it’ll help you heal faster” and she says “well I’m going to tear my stitches and go back to the hospital if I do that.” It’s not worth arguing over, but I’m going back to work across the country tomorrow and I’m stressed and tired and it’s all getting to me. I’m so agitated at the smallest things even when she’s not arguing. I find myself getting short about the stupidest things. I feel AWFUL. This woman raised me with my mom. She’s done everything for me. Not only do I feel like a terrible person for not being able to help her and my mom, but what kind of mom will I be that this tiny bit of time is trying my patience?

Not looking for a pity party, just genuine advice. Thank you