stool change *WARNING*

okay so my almost 7 month old got shots on thursday and today he’s had yellow/seedy/mucus poop. has anyone went through this? im a first time mom but this is definitely a question for second time moms. could it be a food allergy? shot reaction? he’s not breastfed, he’s formula fed and we’ve never had something like this happen before *WARNING* THERE IS A PICTURE. DONT LOOK JUST TO COMMENT SOMETHING RUDE.