That's assuming that Homura got ambushed by the Wraith a day or two after Sayaka's death. We don't even know how much time went by between Sayaka dying, Homura transferring in, and Homura losing her power to the Wraiths. The time between these events could go from anywhere from a few days to a few weeks.
The only confirmation of a timeline after Homura lost her powers was that she spent a few days waiting for her powers to come back, to which Kyubey explained it wouldn't happen. Then she met Wraith Madoka, and spent a week trying to track down the giant Wraith. And then shit started to go down with the mutated giant Wraith. A little bit more than 1 week is the minimum time, while a little bit more than 5 weeks is the absolute maximum time, and the latter is assuming there was little to no delay between Sayaka dying, Homura transferring, and Homura getting her power stolen by the Wraiths.