Bullied. Should I feel guilty about my decision?

I asked a couple months ago concerning taking care of my grandparents when I didn’t want to and I was basically forced to do it. I told my mother in law that August I was no longer going to be taking care of them due to my 4 year old starting Pre K and my husband was fine with that. I emailed my hour person and I may get to go back sooner, just depends on the job openings. I told her that and she told me “well I’ll have to do what I have to”. She is bullying me into staying at a job I hate, isn’t good for my mental health (I’m having panic attacks and anxiety due to this) and I’m slacking on my duties as a mother and wife. I realize it’s a bad situation for her because both parents are refusing to go into a nursing home or have someone else besides me look after them. That’s not fair to me. I have a life too. I’m not even blood! Should I feel guilty about my desicion? Because I sure don’t.