This morning I woke up with a little bit of diarrhea...and although I probably shouldn't have I had a yogurt for breakfast. I went on a run afterward and I felt a little bit of cramping in my left side but I ignored it and thought it was just from eating before running.
I started to feel worse when I took my shower, and now I feel completely terrible!

I feel really nauseous and there's a little bit of cramping in my stomach still. It's kind of gurgaly as well. My stomach started feeling not too great a few days ago as well but it hasn't been this bad.

Is it just a common bug? Or something else?
Also what can I do to feel better?