my baby boy was crying all night

So I have a 5 week old son. Usually he sleeps all day , but in the morning around 1-6am he's awake. (I tried keeping him up in the day but fail to do so) anyways this morning around 4am my son was crying . I got up changed him ,fed him burped him etc. put him down in his basinet and gave him his pacifier. He was quite for a min. He then spit out his pacifier and started crying bad. I didn't know what was wrong since I already did what I can to calm him down. Going forward to 1pm today I woke up to feed my baby and change him etc. when I changed him I noticed he pooped(he poops every 2-3days) his poop was hard and it was only like 3 balls of poop(tmi I know sorry) I wanted to know if this is normal. As I think it's the reason my baby was crying all night because I'm sure he was in pain maybe from constipation . I'm a FTM and don't know what I should do so I wanted to ask some moms on here first before calling his doctor.