Is my frozen milk bad?

My little lady is 2 months old and her bowel movements lately have been yellow and runny (normal) and she's been having them about every other day to three days. Well last night I thawed two bags of milk pumped in November. My husband gave her one of those bags early this morning and I gave her one this afternoon. The milk smelled a little strange, a bit soapy. I've read that's perfectly normal and if baby will still eat it there's no problem. Well she ate both bottles without any concern. But couple hours after the second bottle my girl had a HUGE bowel movement. I'm talking yellow/green and very runny- pooling at the bottom of her diaper. (Tmi, sorry) She's since had two more bm's that haven't been as severe in the last three hours. She's also been fed a couple more times but with freshly expressed milk. She has a happy disposition, nothing out of the normal. She's eating slightly less amounts than normal but more frequently. I also think I may have mastitis (very painful breast, decreased supply, temp of 101, chills/aches) so I can't tell if maybe my milk now is causing her problems. Do y'all think it's diarrhea and related to my stash or do you think it's just coincidence that she's a bit more runny &a frequent? Maybe due to my infection? I'm very concerned, thanks!