My LO, who is now 1 yrs and 4 weeks, seems to be acting very off and more fussy than usual. The only new thing we've introduced is cow's milk. We did a gradual process of formula and breastmilk plus cow's milk. Now it's mostly cow's milk and like 1/4 formula. He's not having diarhea and I'm not noticing any increase in gas. Are there any signs I'm missing?