At this age my dd would often wake around 5am. I would feed her, sometimes that would take 20-40 min. I would change her diaper and let her sit in my lap or hold her or rock her, and then back to sleep for her! If you can handle it, go with a short low key awake time- should likely take all your feed, diaper and "rocking" time. Talk softly to her, etc. I know it's not as nice to just feed and put back but it really helped and eventually I wasn't so frustrated. We'd go back to sleep until about 7:30. Or
Have you tried doing pat/shh to get her back?
Getting her to sleep during the day better or longer will actually improve her nights. You can use pat/shh to extend or create naps too.
Oh, could also be in a growth spurt too if didn't have the 6 week one yet?
