Is it okay to be scared of your mother?

Eh, I have to admit even being eighteen year old when I anger my mom (even over the tiniest of things) she goes ballistic and scares the **** out of me. Whenever I get the vibe that she's angry I tense up and freeze, I can't seem to focus on anything and I turn into a nervous wreck. I keep saying to myself that I'm going to die because she's that scary. I also end up in my bed hiding under the blankets in fear even after she's angry at me. It's hard for me to love my mom if she keeps doing this, I don't know what to do