Baby sleeping schedule ruined???

My daughter used to sleep they the night since she was about 6weeks old she would atleast sleep 8 hours if not more some days. Now she is 13 weeks and she is starting to wake up for late night feeds again. I have no idea why maybe anyone can help me understand? I know she’s still a baby and little.. but I never sleep trained or kept a real schedule because she would do it herself is there something I’m doing wrong?