Way to go--gee, you don't dither around wringing your hands once you make up your mind, do you?
Fluoxetine is generic Prozac. Try to stay away from internet searches on it because there are plenty of horror websites for all the meds. Just know that starting slow and working up to an effective dose works, and at some point after you start it and haven't gotten a dose increase you may start to feel like you are going backwards. It's usually just an increase that's needed. Also, don't stop taking it suddenly. Prozac is usually more forgiving than most, but it varies for different people.
You may feel a little weird for the first couple of days taking it. That's partly what the Xanax is for--to help get through that, and to help with stress and anxiety, and sleep (take as prescribed). Xanax isn't for the long term. Prozac can eventually help with anxiety and depression and other symptoms.
Most of the SSRIs do interfere some with sex drive. If you can stand the idea of meds for a year and that that year may not be the most "romantic" it can be okay. Feeling better is worth a whole lot. But yeah, that's one reason people decide to quit or switch meds. The weight gain or loss is individual--some people gain some people lose.
Give this a week or so before deciding one way or another if it's the med for you, but keep your doc (and us) posted on how it all goes.
It's a relief a little to actually see the doc and get something started, isn't it?