confused

So I just wanted to try and get some advice from you guys because I'm not sure if what's happening is really abuse. When me and my mom gets in arguments she hits me, she never leaves a mark but still slaps/punches me pretty hard when she's mad at me. It's only happened a few times and we normally have a pretty good relationship, but she's sometimes mean to me and says really hurtful stuff, when I'm sassy she calls me a bitch and she always makes me feel guilty for the money it takes to take care of me. I'm just really confused because the first time she physically hit me I told myself she was just really upset but now that it's been repeated I feel really nervous around her.