Stomach bug going around- third time!

Here in the UK there's some stomach thing going around that causes massive diarhea and vomiting. It goes away after about 48 hours and isn't a big deal, but it's gross and causes massive cramping, which makes me freak out that something is wrong (I'm 19 weeks). Today I got the bug again- for the third time!! What am I doing wrong and why do I keep getting this bug?? Anyone else having this issue?? So frustrated 😔