Sometimes I remember when my mother called my therapist and I get so angry

She claimed she called simply to ask how I was doing. Thankfully my therapist was professional and told her that she can't disclose anything. My mother knew it but I don't know what compelled her to call. And she hid it from me, my therapist was the one to tell me. I'm still wondering if it was a control thing, simple curiosity or a test. But at that moment I felt like she tried to take one single thing I was doing just for myself. I felt like going to a therapist wasn't for me from the beginning, but she pressured me. And even when I did as she wanted, she somehow wanted more. Did she want proof that I was actually going? I learned to hide anything going on in my life, good or bad. When I got accepted into a Master's programme I didn't tell her until it was inevitable. When I got into a relationship I didn't introduce him until we were about to live together. Honestly she's not some prying or intrusive person at all and I get wanting to be involved in your children's life but that clashes with my own personality and I tend to be more private and closed off than most people.