How newborn is this baby? It’s pretty normal for babies to have their days and nights mixed up for a while. It’s also normal for babies to have a fussy period toward the end of the day. It’s sort of like the baby’s way of blowing off steam, and you might notice it’s worse after a more stimulating day than a calm one.
If your baby is under two months old, I’d suggest you stick to an “on demand” schedule. Feeding and sleeping should be done when the baby needs it. When he or she is older, you can start to try to regulate naps or keep the baby awake for longer periods during the day.
One thing that will help is to keep the night and day as separate as you can. Dress the baby in clothes in the morning. Don’t keep the rooms too dark when he’s sleeping. At night, change him into pjs and establish a clear routine. Bath, rocking, singing, stories, or soft music. Keep his room dark, with maybe just a soft nightlight. When he wakes up to be fed, don’t turn on all the lights and the TV. Try to keep him from fully waking up with a lot of activity. He will learn to differentiate between night and day and settle into a more predictable routine. For now, sleep when he sleeps like others have suggested.
It’s not for everyone, but we let all our kids sleep with us when they were babies. Look into safe ways to cosleep and see if it will work for you. We loved it because it was the best way for all us of to get the most sleep right from the start.