My 6 week old is having a growth spurt. He normally has 5oz he's hungry again very quickly. Last night he had 7oz and was fine. I gave him 7 today which he took and wasn't sick. Shortly after (5 mins or so) he was crying and whimpering which was heart breaking. He did burp plenty so don't think it was that. Worried now that I mixed formula wrong! He's sleeping contentedly on my husband now but cried when I tried to lie him flat (which is usually fine). Any thoughts for a worried mum??