Unusually early and painful period

My period is usually extremely regular and predictable. I always can sense when I’m getting it - even if I start bleeding in the middle of the night, I wake up soon after it starts. I usually have very slight cramps or none at all.

This month, though, my period came quite early and I woke up with extremely painful cramps (this never happens - usually my cramps start an hour or so after it starts). I was in bed all day and felt sick. Overall this cycle feels quite different from what I’m used to.

I started running this past week. Could that have brought on these changes? I did go from not running at all to running every day, so it might have caused some hormonal imbalance or something. Is this possible? And does anyone have any tips/suggestions for cycle regulation? This has never been an issue for the entire time I’ve been menstruating, so I could use some input.