Sickness and diarrhea before BFP?

I used Opks this month and caught my most fertile day as the test line was so much darker than the control line, I’m now 10/11 DPO and woke up feeling ‘hungover’ even though I wasn’t then the diarrhea started (sorry tmi), I had to come home from work as I felt that bad. I was sick once when coming home but I still have the diarrhea and stomach cramps. It’s weird because if it’s a bug I normally know where I’ve got it from but none of my family or friends are sick. I had this with my first pregnancy but I thought it was a big as only lasted a few days, anyone else experienced this?