Green poop

Mkmt
*TMI alert*
The last 3-4 days, my poop has gotten progressively darker green. Today I had diahreah and it was definitely green!
I looked it up online and some say it's your diet (lots of leafy greens) but j haven't eaten any of those recently. I did eat two dark blue frosting cupcakes yesterday...
Or it's the iron in your prenatal vitamin. Since this was our 6th <a href="https://glowing.com/glow-fertility-program">IVF</a>, I've basically been on prenatal vitamins for like 18 months and never had this before. 
Anyone have something similar? Anything to worry about?