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 IVF, I've basically been on prenatal vitamins for like 18 months and never had this before. 
Anyone have something similar? Anything to worry about?