I don’t know how to feel right now

So my boyfriend took his pet to the vet yesterday. And come to find out the medication he got sent home with was a needle injection. So he asks me can I help since it requires two people I said I never did it before. So as we was about to try I freaked out because I was scared his animal tried to bite me I told him to give me a few to prepare. He started screaming at me saying his animal gonna die and he gonna hold me accountable and that he was just gonna go back to the vet and have them do it! I eventually did it but I was terrified I never done it before. He made me feel so low just by saying all that 😭😭😭😭😭