The truth is you won't get over it and you probably won't trust her again. While you had a right to speak to your mom candidly about your recent experience, it's not right that you did it at her workplace because you knew he worked there too. He probably got into some trouble and she's retalitating the only way she knows how, withholding what she percieves as love. It's not right to put the kids in the middle but so often parents do it.
So to ease your own mind you should adopt these ideas,
It's never what you say that makes trouble it's how someone elses mind twists it.
So all you can do is
*be honest when speaking
*don't make assumptions
*don't take anything personally
*do the best you can
And when someone gets offended by the truth, well, let them walk away, most users will be back and they hate themselves for it. There's nothing you can do to regain what you have lost. It's better not to dwell on all you did and was never paid back for.
I just recently had the same kind of experience. My cousin who is closer to me than my own sister wanted ideas to help her pre-teen avoid an eating disorder. I really think the girl's boyfriend is at the root of it so I told the mom so and she snapped at me. She thought I was blaming her and told me she didn't want to speak to me again. Her own sister had done the same thing the day before when I posted "an offensive question" in a survey I sent her on MySpace. My mother and sister are also this way. "I will never talk to you again!!!"
But my dear cousin wrote me two days later, my sister and mother start calling and writing emails when they're trying to butter me up for something. Eventually the other cousin will come around to. It hurts terribly but sometimes you just have to accept that they are that way and stop letting it get to you.
P.S. I did all the same things for each of them, lending money, hauling them around, moving them, babysitting for free and money that was never paid. I also lost 2 houses because I wasn't paid for daycare or their share of the "rent" and utilities.
Believe me real friends won't ever treat you that way. Find some and you'll feel so much better.