Um... I feel like there seems to be a lack of understanding and sympathy from both parties. While it was wrong for her to be hostile towards you for wanting to stay home (and I understand that running errands in the summer can be exhausting), have you thought about what she was thinking when she wanted to go with you?
Perhaps she wanted your company because she was having an emotional day. Maybe she wanted to have you come along so that you could pick out something you'd be excited about for dinner. Maybe it was completely arbitrary. Still, sympathy can go a long way towards abating irritation.