Why won’t my 5 week old sleep?

💙💕

He was sleeping at night great. Only woke up every 3 hr for food and diaper change. Now he won’t sleep at night at all. I had to put him on formula last week finally but he’s fine during the day. The only thing i’ve noticed it’s done is change his poop schedule from daily to every few days. And sometimes spits up. Last night was miserable. I’ve got the gas drops. Just looking for any advice. Thanks