Hair thinning, short period = problems!

Hello. My period arrived after a 40 day cycle. However, it was only heavy for one day out of the three days I bled. I’ve read woman being pregnant and having a period....although I was raised to believe that a period was a period and not pregnancy.

Yes, I’ve tested and negative. There was no unprotected sex....however there’s always a chance.

Lately I’ve been stressed with my job and personal life. Would this contribute to my lack of period, my hair thinning, acne, sleep etc?