My baby was such a great sleeper. At 6.5 months +

Ann
She started waking up after 4-5hrs of sleep. I'll feed her and it takes her a long time to fall back alseep. She also used to wake up at 8..not she wakes up at 6:30. I got so spoiled Coz she was finally sleeping 9-11hr stretches from 5 months to 6 months. Now I'm constantly exhausted. Is anyone else's baby waking up more often? I hope this is just a phase!