Has anyone ever had experience with losing their period from exercising / stress?

I'm generally an active person and workout 2-4times/week before (aerial classes and jogging) but I got a knee injury and started walking instead. Since I'm performing in a month and wanted to tone up my body, I've been going to the gym at least 3x/week, I also picked up muay thai as i enjoy it and still walk (mostly 30min incline walk on the treadmill now).

I don't count my calories but I try to eat as much whole foods and as healthy as possible. My period has been getting later and later for the past 3 months and this month I'm late by 2.5 weeks already.

And no, I’m not pregnant because I took dozens of tests and they’re all negative. I was really stressed out 2 weeks ago from work and family stuff but it’s gotten so much better now.