When you're immediately recovering from surgery, it's more that your body is focusing all its healing capabilities on that - prioritizing recovery over everything else. I appreciated that, really, since I'd rather get a cold than an infection in the new vagina.

Once you're past the initial recovery phase, there's still a lot of work to be done in rebuilding the lost resources, so you'll probably still be easily tired and a little fragile for months. Women also do seem to be more susceptible to minor illnesses, and the combination of castration + estrogen may well make us closer to cis women that way.
(My close friend who had a hysterectomy said the same thing, that it was over a year before she was back to 100%.)