Shortened periods

I have three children. Recently in this past years I’ve noticed major changes in my period. I’ve seen a gyno but she doesn’t feel like there’s anything abnormal going on with my body that it’s just changes due to age. I’m concerned because I used to have a 7 day period, then it went to 4 and now it’s literally a 2 day period. Has anyone every personally

Experienced this as it is truly concerning. We would like to have another child but it makes me even question is it possible if I’m having these changes in my body.