5 month old not sleeping

She will not sleep at night anymore and we are going crazy. She did have an ear infection and has been on antibiotics for a few days now but even before then she has not been sleeping at all. She will go down herself anytime between 9-1030 after a bath and eating. Then will wake up anytime from 12-2 and then after that she will not go back to sleep until 5 or 6 when it's time for us to get ready for work, she goes to Daycare at 7. Very fussy nothing comforts her. We both work long days and it's getting exhausting. She naps fine at Daycare or when we are off. She started sleeping 11 hours at night for a month before this happened. We rotate nights but my SO is getting tired of it he works in the heat all day and getting no sleep isn't gonna cut it. Any tips?