Conformation.

you start going to class regularly, you kind of expect a bigger response but it seems no one really knew you so your disappearance and replacement is a minor thing. Classes go pretty well, you expected to be worse at math but that was stupid of you. It also seems that after that first day your sex drive isn't crazy any more, you get yourself off once or twice a day and you are happy. That is good because in that next week you get to be about as fat as you were before so dating prospects go down sharply. You figure you could still get a guy but you aren't overly concerned.

on day 24 you become very concerned you have gotten huge and can barely navigate. you also seem to be eating the strangest things. you go into the hospital the doctor sees you right away and starts poking and prodding. After a few minutes he takes a little blood and leaves, when he returns he says ? congratulations" you look around, confused "um... why?" he looks up from his clipboard "well because you are pregnant."