Agree with Soundi.
Were you in the wrong with this mother? If so, did you apologize to her? If your MIL is horrible toward you…she’s not going to change unless she decides to snap out if herself. If she’s made up her mind to hate you…there’s nothing you can do change her. Bottom line: You can’t change her. And frequently stressing over someone who isn’t going to change is only going to take its toll on YOU. And who knows? Maybe your MIL wants you to get upset…maybe she wants her comments/actions to get under your skin. Don’t give her the satisfaction. You can’t change her but you can change how you react to her. Simply…don’t react to her. Kill her with kindness. When the offender sees that we’re calm as a cucumber and happy as a clam…it burns them. I know it’s easier said than done…but if your MIL is the main source of contention here…try not to let her get to you.