‘Tit for Tat’

Last week, my sister called to ask if I could go to a shop for her. I said I couldn’t go because I have severe PGP that causes a very dramatic limp and limits me greatly. I also suffer with HG and medicate myself several times a day, meaning I sleep a lot or am constantly drowsy if awake . I did go to this specific shop last week because my hubby drove us all (I even paid for her things- not that it’s important). She was really off and then hung up on me. (When I say off, she was saying “You can drive there” - I cannot drive due to my medication. Then it was “Walk then” - The 15 minute walk each way would take me over an hour each way. Her final retort was that I should “Take a bus” - No buses go anywhere close to the shop. It’s actually a major detour). Today I asked her if she wouldn’t mind grabbing me some things from a shop she is heading to on Monday. In my area, it is really hard to find these items local, and I only asked because I knew she was going. I said I would send her the money and gladly cover her costs as a thank you. Instead, she told me where the shop is (which i already know). She then made a vague reference to when she had asked me to go to a shop the week before. I just said “Oh, thank you. Sorry to have disturbed you” and hung up. I know it is not her job to do this for me. She has still been off with me ever since I told her I couldn’t go to the shop for her. I don’t even know if I have the right to be upset about this. Not so much the fact she wouldn’t get the things, just her attitude towards me.