Right, it may be 厭奶期! My bb also came across such period 4 wks ago when she was 5 months old. I tried many method without success...... Finally, I changed all her 奶咀 (to the size 5 months+) cos I thought she might become bigger and no more patient for the slow-flowing 奶咀. Ha! Ha! It works!
My bb also adjusts her own diet from 5 times a day to 4 times a day after I changed her 奶咀. She drinks more milk (around 800ml) per day from then onwards. So, don't worry! Give your bb some time la!!