advice please

so….

i need an excuse for work. i just had a female medical procedure done yesterday, and i have a note from the dr. for work that says i cant lift anything over 5 pounds for the next two weeks. i told my manager the truth about what happened, but everyone else in my office is very nosy and will be asking lots of questions when i go back to work monday. my job requires a lot of heavy lifting, pulling, etc — lots of things i cant do for the next two weeks. 

i feel my medical history is my personal business, and because this was a "female" procedure, i’d like to keep it as private as possible.

ive been looking online for types of back injuries to lie and tell everyone else why i cant perform my usual duties.

so far, i havent found anything that would work. any ideas???