I am 46 and have had my period since I was 9 and now it comes every 25 days and the first few days I have to run to the bathroom with big clots help?

Perimenopause. This is most likely related to the perimenopausal transition, however, you should see your doctor to see if a biopsy may be warranted. There are medications available that can alleviated your symptoms.
Changing Periods. You are premenopausal and your hormones are tapering and what you are going through may be normal physiological occurence.But discuss with your gynecologist at next visit.