Menstral Blood Clots

I am 36-years old and on Wednesday (6/23) my menstral cycle started, then on Thursday (6/24) there was nothing, and today Friday (6/25) I woke up, went to the bathroom and had blood and blood clots.  I went put on 2-tampons within 2-hours. I have not had a problem up until now. Could the blood clots be from my cycle going away on Thursday?

Also it seems the older I get the more problems I am experiencing
with my cycle, such as pain when cycle is about to start, or cycle may stay for 3-4 days then go away till the next month, and I also may pass one or two small blood clots.

I have a Dr. appt. for July 7th.  Could this be the beginning stages of menopause?  HELP!!