My 3 month DS has started to refuse to take his bottle and I don't know why. I'm breast feeding but gave him bottles of expressed milk and formula since 2 to 3 weeks without any problems. For the last month we've given him a bottle of formula at night in the hope of getting him to sleep through (yeah right). He always gulped it down - he's a real fatty - but for the last 4 nights has just refused - just screams and goes mental when the bottle is in his mouth. Any ideas why? Really starting to concern me. Haven't changed bottles or formula or anything.