You made it most if not all of the way through season 8 then, unless you skipped a bunch. XD
As for the regeneration thing, like Moa said, Time Lords can regenerate into different genders. They've alluded to this a few times, such as when 11 mentions The Corsair in "The Doctor's Wife."
As for the Master being resurrected...that always happens sooner or later, often with minimal explanation to distract us. =P