TMI- metformin, spinach, and diarrhea

So I started metformin 2 weeks ago. Started having diarrhea, which I expected and it was pretty normal looking. But for three days now, it's been dark green. Eeww I know. I'm pretty worried now.

However, last week (about 6 days ago) I had a spinach salad for lunch. Could the spinach be changing the color 4 days after I ate it and make it stay dark green for 3 days in a row??? I didn't think the spinach would sit in my body for 4 days and then start changing the color. So I'm worried it's something else. Called the doc but their closed on weekends.

Let me know! Thnx