Calm yourself down first, you can’t think straight if you are fuming/feeling stressed out.
Maybe your husband’s POV is that he wants to let you cool down and rest properly but probably did it in a wrong way for not informing. My husband would have just left himself and leave the kid with me 🙃. The thing about guys is that they like to just leave instead of debating whereas girls usually go all Conan mode.
Also, you mentioned that they are heading to the clinic so I personally find it ok, after 1, my husband brings LO to all vaccinations while I stay home. Take a rest for the time being, after you cooled down, can make dinner then let him know that you appreciate him for taking baby to clinic (guys usually take the soft approach). This way, can avoid another fight and also, he will try to understand you more.