Sudden change in periods

My cycle had been regular. Every 27 days. You know of course sometimes it'd be off to 28 days. But it was very regular.
Until 3 months ago. 
I changed nothing in my lifestyle. My weight stayed the same. I wasn't stressed. I was healthy.
Then I suddenly had a 43 day cycle... 2 weeks late. I couldn't believe it.
Well. Then the next month. I got my period on day 34 and this month was 32.
Why is this happwneing??? I mean like I've said. I have had no changes to my lifestyle and I mean even my sex life has stayed the same for the past 3 years.
& will this effect my ovulation and my chances of getting pregnant?
But most importantly: WHYYYY

Glow Resources

Let’s Glow

Glow is here for you on your path to pregnancy

Glow helps you navigate your fertility journey with smart tools, personalized insights, and guidance from medical experts who understand what matters most.

25+ million

Users

4.8 stars

200k+ app ratings

20+

Medical advisors