Ay mama, first thing, kung worried ka talaga or may doubt pa, best is makita ng doctor para peace of mind mo, lalo na if it happens again!
But honestly, oo, poop color ng breastfed babies talagang nag-achange depending sa diet mo, and green poop ay normal din especially during transition sa bottle feeding or if may slight tummy adjustment. One-time lang naman, so likely okay lang yan! Newborn poop is such a mystery, diba, one moment yellow, next moment parang gulay na I'd just watch out if it happens ulit or may iba pang signs like fussiness, then that's the cue to call the pedia. You're not paranoid, you're just a good mama paying attention!