BF baby poop?

Hey all,

My little one is 17 weeks old and she’s breastfed, apart from about 60mls every night of formula with her reflux medication.

Lately her nappies are VERY watery and have little lumps of white in them? (See front part of nappy) It’s almost like curdled milk? I’m assuming this is normal. They smell quite sour. She only poops once every 2 days or so.