Rough couple of days

So, our perfect little boy hasn't been so perfect the past few days! He is like a different baby. Yes, we are blessed to have him sleep from 9:30p.m. to around 6a.m. then we just feed him and he sleeps until 9 or 10am. So we realize that we are very lucky to have that time to sleep. BUT...the past few days he won't sleep at all during the day even though he is so incredibly tired! It is the weirdest thing. He screams and does his tired cry, and even if we do get him to sleep, once we put him in his crib, 10 minutes later he is up screaming again. We are at a loss! We thought it was him being backed up cuz we switched his formula and his poops were a little on the harder side, but that has passed now and he just cries non stop if he isn't eating. We are thinking of switching him back to the formula we had him on before because this is getting ridiculous! We don't think it's anything serious because he does sleep so good during the night. We think that if it was something serious it would be all the time, day or night. So, if anyone has any suggestions for me, I would much appreciate it! Mine and James' sanity would much appreciate it as well=)