Sister in Law Vomiting

Today we were due to go to my in laws for a bbq but my sister in law (who lives there) was up all night vomiting and had a fever. I have said that I am not going as I’m 22+5 and I don’t want to risk catching a fever.

She is now saying (less than 12 hours later) that she feels fine. My husband feels that he has to go but they are making a bit of an issue about be not going. Am I really being over sensitive? X