Irregular Period Explanation?

Hey,

Recently I have had periods that have occurred very close together (seen in photo). My normal cycle length is around 26-28 days and lasts around 5-6 days. I'm currently in my senior year of high school and going through a lot of stress with schoolwork, exams, papers, and projects so I assumed that the irregularities were caused by the stress as I had read online. But after getting my period for the third time this month, I'm not too sure anymore 🤔

I'm a relatively healthy person: I have a pretty healthy diet, run on the weekends, walk my dogs every day, pretty happy. I'm ~110 lb. and 5 foot 4.

Any sort of advice or ideas would be greatly appreciated!

Thank you!!

(I'll be going to the doctor if this happens one more time)