cycle changes anyone else or is thisnormal ?

almost 41. Cycle length have gotten shorter. From 28-30 to 17-23. My period has also changed. I have always had 5 day periods with Days 1 and 5 light bleeding and days 2-4 heavy bleeding with lots of large clots. Now I just spot very very very lightly on day 1 and 2 then on days 3 and 4, I have heavy bleeding lots of large clots. Day 5 just lightly spot again. FF says my luteal phase is really varied even though I temp at same time daily. In addition sometimes it says I ovulated during one of the 5 days of my period??? I'm so confused. I also never have cramps