How to not let my mom have such an impact

Im 19 almost 20 and live with my bf in an apt. She makes comments about everything if the apt isnt spotless when she comes over or something. She came to me at my new job to sign some papers and i was super rushed with her and not impolite but i couldve been better. I was just nervous bc ya know new job and all. And after work she said i embarrassed her. Now i feel like complete shit. How do i not let her affect me and my mood so much. I still feel like she controls me and that i cant actually do what i want or be an adult. She is a wonderful mother but definitely is overwhelming and involved.