Baby suddenly gassy & fussy

My baby boy is 2 weeks and 2 days old. He was such a great baby up until he hit 2 weeks. He only cried when he was hungry and he slept in his pack n play like a champ. Now all the sudden he is super fussy and I can tell hes in pain. He wont let me put him down in his pack n play. I gave him gripe water for the first time on the 4th of July and it knocked him out for 4 hours. He is breastfed and we also use a bottle once in a while. Im wondering if its something in my diet. But I'm not eating anything different than I was. Did this happen to anyone elses little one? I feel so bad for him. :