DOn't worry, it happens to all babies... My son only drank 1.5-3 oz when he was 2-3 months old due to 厭奶期. But his weight increases steadily, that's why I just let it go. Now he is around 3m3w old, he drinks 5.5oz as usual... I guess the 厭奶期 finished. Don't worry as long as his weight doesn't drop...