I took Lexapro (in Canada it's called Cipralex but it's the exact same thing) for about a year, I've only just switched to Effexor XR because the Cipralex was no longer giving me any results.
You probably won't like hearing this but I did gain some weight on Lexapro, but I honestly didn't care because IT WORKED. It took care of my symptoms and I could finally get back to a semi-normal life. The other prevalent side effect for me was that I was really sleepy, but that went away after a couple of weeks.
I was really nervous at first as well, but my anxiety was to the point that I would have tried anything, and it was really exciting when I realized what a difference the medication was making. Of course it won't fix everything, but for me it made enough of a difference that I could get back on track. Keep in mind that if you don't like it, you can always switch to something else or stop it entirely (though DO NOT stop it all at once and on your own, that's really dangerous to do with anti-depressants).
Good luck!