I hit my kid today and I don't know what to do
So background is that I'm a 100% solo parent and I'm very tolerant and understanding of age appropriate behavior. I don't always have enough support outside of daycare hours when I'm working for me time to recharge. I am extremely morally against corporal punishment although physical punishment was used on me growing up (more like overly aggressive restraining than hitting). Important: I'm also a DV survivor and was diagnosed less than a year ago with CPTSD, which I'm in the process of seeking treatment for (very few resources where I live, long waiting lists).
So to today, my kiddo is 2.3 and he's very into hitting, biting, pinching, grabbing, climbing on me, screeching etc. Developmentally normal 2-year old stuff. I redirect and explain appropriate behavior. It's really important to teach him to respect me and today I failed really badly. We had an easy morning, he got lots of attention while we read books and ate breakfast outdoors. Mid-morning I really wanted time to recline with a coffee and to read my grown up book. He wouldn't stop climbing on me, wasn't responding to redirection. At one point while I was sipping my coffee, he smacked the cup hard into my teeth. As a DV survivor the impact to my face was really, really triggering to me (normally kiddo smacks me in the arm and not nearly that hard) and out of pure reflex I smacked him in the face. What scares me is that it wasn't a decision, it was a split-second reflex from my primal brain defending myself from a perceived threat.
We both dissolved into tears and I apologized and we cuddled for a long time. He's over it now (this happened 45 minutes ago) but I'm still shaken and crying. I feel like I have a low tolerance for hitting relative to people without C-PTSD and I wish there was some way to fix hitting behavior quickly. But it's impossible to just shut it down instantly. I feel like such a bad mom and person and I don't trust myself.
I'm really not looking for advice, I feel like I know all the parenting advice to address hitting in toddlers. I don't need any therapy advice, I have medical professionals for that. I guess I'd like to hear that it's going to be okay, and maybe if anyone else has had an isolated experience like this and the reaction didn't happen again, please tell me because I'm most scared about it happening again.