Feeling like the worst mother in the world.......?

I had a pretty crappy day today and I was extremely tired and basically lost my temper on my one year old son. I didn't hurt him or anything-just yelling, but I know I did wrong. I cried and hugged him and told him I was sorry, but I still feel like I'm the most evil person in the world. I was abused as a child-physically, emotionally, and sexually-so I'm very paranoid about continuing the cycle with my son. How can I stop this cycle before it continues?