OP....you mentioned that when things get better for you financially you are going to get a chiro for her. If she is hurting that could account for part of her attitude. If she hurts continuing to ride her will not cure any problem. She will simply continue to hurt. I am certainly no expert by any means but I do know how fussy they can be when they hurt and they can't tell us, except by their behavior. If you can possibly have her checked at least you would know if she needs treatment or she really is just pissy.
A number of years ago a chiro and saddle fitting helped solve a lot of problems I was having with my mare...interestingly and lovingly called Pissy Missy.
Good luck to both of you.
If you ever find yourself in a fair fight, it's because your tactics suck. ~ Marine 1SGT J. Reifinger