How to tell my mom ☹️

Please don't be mean or rude. I just turned 17 and This was a huge mistake. I am on birth control pills and me and my boyfriend thought I was protected from pregnancy completely. As far as I'm concerned he was pulling out. And he did because it would get on the sheets or on me. I know it only takes a little bit to get pregnant. But how?!?? I thought birth control was suppose to protect me from this 😥 I'm not ready for a child. I'm still in high school and I don't even know how to tell my mom. I took two test to be sure and both came up positive as you can see. My period doesn't come anyway since I was on birth control so what made me take the test was that I was feeling strong sharp pains in my abdomen. And not being able to keep any food down. I have lost 4 pounds. My mom knows something is up but I just don't even know what to say. Help me please 😥😥😥😥 I feel like a failure