I went back to work 2 weeks ago, and ever since that exact day, her routine is all changed.
Before I went back to work, she used to STTN everyday from 6 weeks on. Now she wakes up at least 3-5x per night to feed.
Before I went back to work, she used to be mostly BF directly from the boob with the occasional bottle of EBM of 3.5 oz. Now she eats 4.5-5 oz per bottle during the day 3x a day.
So what gives? It seems like she's eating tons during the daytime and tons during the nighttime. She went from eating 5-6 times a day to about 8-10 times a day and she's gaining weight rather quickly too (about 2 lbs in 2.5 weeks). Is this a crazy growth spurt time or is the bottles during the day making her stomach stretch, making her eat more at each feeding session? If it is a growth spurt, I didn't realize they lasted for two weeks

Any help or sharing would be great.
(Sorry this was so long)
Re: Back-to-work issues (feeding, sleep)
Another thing you might try too if you aren't already is using a bottle for bf babies. I use medela, but I'm sure there are others.
Sorry such a long post, but she will get a routine back again soon!
The amount your daughter is consuming is about the same as what DS was taking in at daycare at that age. It seemed like a lot to me at the time because I never had to quantify the amount of BM was consuming. The good news is that DS has not increased the amount of BM that he takes at daycare.
Your daughter could also be going through a growth spurt, babies grow a lot faster when they are younger, but it slows down. At beginning, DS was putting a little over a pound a week, now he's starting to level off.
After a couple of more weeks, you and the daycare provider will have a better idea of what your daughter needs during the day.
Re: STTN - that was probably going to end soon regardless of starting daycare. Sleeping habits change based on the different developmental stages. DS wakes up during the night for any number of reasons: rolling over in the middle of the night, teething, 4 month wakeful period . . . . It is all good, it means he's growing!
GL!