Ang poop niya actually normal pa yan for a 2-month-old on mixed feeding, lalo na kung breastfed siya kase naturally frequent ang poops ng breastfed babies! Yung yellow and seedy texture is exactly what you want to see, sign na well-fed siya. A few of my mum friends din nag-worry about this with their second babies pero ang pediatrician nila nag-assure na ok lang up to 5-10 times a day at that age, as long as wala siyang signs ng discomfort, fever, o blood sa poop. I'd still check with your doc just to be sure everything's on track, especially since you're mixing breast and formula, they might want to assess kung balanced na ang intake niya, pero honestly sounds like normal baby poop to me!