Baby not eating while I'm at work....

Good morning girls, I went back to work 2 weeks ago and am starting to encounter some issues. The first few days, DD2 (6.5 months old now) took her bottles ok. Last week, she started taking less and less of her bottles. Thursday night, DD1 got sick with a stomach bug and spent all night vomitting. Friday a.m. she was fine. DD2 didn't nurse great much of the weekend, had wet diapers and all, but just didn't nurse great. I thought maybe she had a milder version of DD!'s bug.  Monday she had vaccinations. She didn't handle them well, so I blamed her being off on that.  But now it's Friday and things still just aren't right. All week, she has only taken about 1.5 oz of pumped milk each feeding while I am gone. So, today, I fed her at 7:30 this am before I left and at 10:30 she had 1.5 ounces. At 12:30, she had 1.5 oz. My supply seems ok when I pump at work (I ahve an oversupply and have pumped 2 times a day while at work, getting a total of 14-15 oz) and her sessions with me seem ok, so I wonder if she is just holding out for me.  She HAS been spitting up some, which she never did. And twice this week (about an hour after eating after I got home from work), she had full blown projectile vommiting.  She certainly isn't sleeping as well at night anymore either. She originally slept 8-7 since 6 weeks and over the past 1.5 weeks, every night she wakes around 2, then again at 5-5:30. I certainly don't mind as it means I get the milk into her and it seems like classic reverse cycling. She is truly one of the happiest babies I have ever seen and with all this going on, she is just looking wiped out. I am just not really certain how to handle this. Do I try a sippy cup, diff't bottles, diff't schedule? Does anyone have any suggestions on how to handle this?  Thanks so much.