Hope it sounds like you feel hurt and vulnerable and really need to protect yourself right now. Quitting is a good way to help yourself feel safe again. Ts response hurt you so quitting is a way of making sure - right now in this moment - that T doesn't hurt you again. Sending that email to quit is a tool to help you self-regulate. Being exposed by sharing your email with him and getting a reply that wasn't the reply that you needed must feel so raw and exposed and open to attack. It makes total sense that you need to immediately pull back and protect you.
What else can you do that will help you feel calmer and safer?