Job stress

I work for a company & I love the company I work for, however i take a lot of blame from our customers if something doesn’t go their way. We had a person who didn’t make her payment on time who took it upon herself to call a federal Department and blame myself and I keep a call log and haven’t spoke with her in over 3 months. I’m 11 weeks pregnant and it’s becoming overbearing and stressful. Does anyone have any advice on how to stay calm