Fever during implantation?

So I've been ttc for 18 months now, and tracking on Glow since October. Since I started tracking I've noticed that three times now I've experience low grade fever, chills and flu-like symptoms around the time in my cycle when implantation is supposed to occur. I usually take a Tylenol and the symptoms go away within 24 hours. Does anyone else experience this during the implantation time in their cycle? I'm wondering what's causing it. Three times seems more than just as coincidence.