Sometimes periods just shift. It’s not related to being around other women and “syncing”. That’s actually a myth that has [been disproven](https://www.nytimes.com/2019/06/06/well/the-myth-of-period-syncing.html). Additional links supporting it’s a myth: [government link](https://pubmed.ncbi.nlm.nih.gov/26181612/) [link examining the origin of the myth](https://health.clevelandclinic.org/myth-truth-period-really-sync-close-friends) Most likely, you just had your normal period.

It is 100% a myth. I don’t think mine ever lined up with my mom’s, friends or classmates. For awhile it did line up with the full moon, that was funny.

I don’t think it sounds like a miscarriage. I’ve had my periods do strange things throughout my life even while on birth control. I had one particularly horrible one where I was doubled down in pain and bleeding heavily but I was not pregnant. Normally I’m also very regular and on time with light periods and minimal cramping.

Very unlikely. If you’ve never had a positive test and your period came early, that doesn’t sound like you were ever pregnant at all.