anyone else's baby?

Ok so my LO is 6 months old and he usually eats 8 ounces every 4 hours and about 3 weeks ago he started only eating 4 ounces every 4 hours so I took him in to get weighed to make sure he wasn't losing weight and the doctor said he might just not being growing much right now and not to worry as long as he's still eating and not getting dehydrated so a couple days later he started eating his 8 ounces again and now he's back to only eating 4 ounces and every 4 hours. It just worries me so much that he's not eating like normal. Anyone