D.W.
As a working mom, myself, I struggled with the same thing. To me, as an outside sales representative at the time with a large territory and lots of driving time, my safety was paramount. When our kids woke-up, I brought them into bed to have as much of an opportunity to sleep as possible.
I've not had a good night's sleep in about 10 years, so having young kids only compounds the issue.
Reading your post, I personally believe your daughter is simply going through one of many changes in her sleep patterns as she ages and changes developmentally - I think her new struggles with sleep are more to do with that and less to do with some of the other changes.
We have 2 kids. One is 3.5 and is an AWFUL sleeper. He always has been despite very little co-sleeping. Our daughter just turned 2. She co-slept almost from the beginning because she was so colicky, and then when I was going through chemo (beginning at week 11 for her), it became a necessity as I physically needed to rest more.
She's our ROCK STAR sleeper. She was in bed with me every night for the first year and now gets herself to sleep and sleeps hard through the night (unless sick).
My advice is to do what works for you so you can be the best mom/employee you can. If it's having her in bed with you temporarily, so be it if it works.
Good luck!