Help, baby wont sleep

Brittany
My son will be 8 months on the 13th and has he's days and nights mixed up. We. Start our nightly routine around 7 or so. Feed baby food, bath, then bottle. He goes to sleep usually for couple hours or more, but then wakes up wide awake. And doesn't go back to sleep until about 3. During they day he gets cranky around being awake at about the 2 hour mark, but at night its a different story. He has only recently started this in the last two weeks. We haven't change his schedule for him to act like this. I have gotten him up early trying to get his schedule back, but nothing works. This mommy is tired and need her nights back. Any help, advice, tips is appreciated. Thanks in advance.