Meredith posed a very good question in the comments, so I'm going to answer it since I actually know the answer for this one! :)
Estrogen in the form of the birth control pill is administered to somewhat regulate the body and especially to shrink the ovaries prior to an IVF cycle. Through ovarian stimulating drugs (in my case, Gonal-F), the ovaries are grown to extremes. The typical size of a non-stimmed ovary is about the size of an almond. Through the IVF process of stimulating the production of egg-filled follicles, the ovaries can become as large as grapefruits.
And I'm complaining about some cramps.
Keep the questions and comments coming! Like I said - I'm trying to learn everything I need to know, but it is SO MUCH.