Help with 15 week old?

My baby used to sleep insanely well, she's knock out around 10pm, wake up at 5am, and fall back asleep within minutes after changing and feeding, then wouldnt wake up till 11am, we have the same routine everynight, bathe, lullabies, feed, and bam knocks right out, but lately even in her afternoon naps she'll start to cry like shes really scared, multiple times, she'll have her eyes closed and is very difficult to console unless we wake her up or my wife breastfeeds her, she'll eat for 5 minutes, knock out and within 20 minutes again, she'll scream and cry like something is scaring her. Could this be a sleep regression? We're keeping the same routine, except my wife now feeds her throuout the night laying down in a side ways position, doesnt seem to be pain because she doesnt scrunch up her bottom or anything of the sort. Help !!