Lexapro did NOTHING for me. No side effects, but no good effects either. Theoretically, you're supposed to give it a full 6-8 wks at a "therapeutic" dose to see if an antidepressant is going to work for you or not, but a lot of studies they've done recently show that most of the positive effects from SSRIs and SNRIs, if they're going to occur, happen in the first week or two. If it were me, I might give it another week or two, but then I'd ask my doctor about switching to something else. 10 mg/day is kinda the low end of the spectrum, it's usually the starting dose. You can go up to 20 mg/day (obviously I'd discuss this with your doc), but maybe you're just not at a high enough dose yet.
Hope it ends up working for you.