Well, it was a retrospective diagnosis, but I am 95% sure it was correct. I had the classic symptoms of a Yersinia infection, and I was IgA positive for Yersinia Enterocolitica when I was first tested for Yersinia about 5 months after I had fallen ill.
Taking a quick look at the symptoms of acute Yersinia enterocolitica, they look very similar to the symptoms of acute coxsackievirus B infection, especially the right lower quadrant pain (though I think coxsackievirus B can cause pain in both lower quadrants). Dr Chia talks about these acute coxsackievirus B symptoms in the Invest in ME conference videos. I suggest considering an alternative diagnosis: that you had an acute coxsackievirus B gastrointestinal infection, a virus strongly linked to ME/CFS, and it was this which kicked off your ME/CFS.