Had my period during sex

I got my period while having sex with my boyfriend, and I thought if this ever happened it wouldn't be a big deal because we have been together for a little over a year, so we are very close and comfortable with one another. He got really grossed out tho(which I guess is understandable), and he would barely look at me afterwards :/ when I went to the store for tampons he even said I should probably just go home, and that he had something to do anyways. It's making me feel disgusting and sad , I didn't expect this to be something that would make him so upset