I’m a terrible mother

I’ve been having a rough time and have been experiencing really bad rage . The last time I’ve felt this way was at a teenager going through depression/ anxiety and self harming . When I would feel the rage hurting myself was the only way to make it go away or at least that’s how I felt . It would come on fast with no warning and I would end up hurting myself . I thought it went away for good but has come back after I had my second in September . I then thought it went away again because I wasn’t feeling it but now it’s back . My oldest has been testing me a lot and isn’t listening to anything , hurting her sister , and doing things we tell her not too. I don’t like spanking but have found myself doing that more . It feels abusive and I would rather hurt myself then my child. I know I need to get my emotions in check . She’s probably acting out because she sees me get angry . I don’t know what to do and I feel like an awful terrible mother who doesn’t deserve her kids . I want to go fall in a hole after I spank her .