Why I Am Getting My Periods Longer?

I am 47 yrs old and I have been on my period for 25 days now. 2 days in there it slowed down like it was going to stop but only picked back up and heavy. I have noticed alot of large clots, more than usual. I do not feel bad, just tired, it just feels like a normal period. I have never had one last this long. What can you tell me?