You can take 40mg of Lexapro? I thought the highest was 20.
Regardless, Lexapro just might not be the med for you. It can work wonders for some people apparently, but it did absolutely nothing for me either. It didn't give me positive effects, side effects, it was just like being on no medication at all. Granted I took the medication alone, back when they thought I was suffering from a unipolar depressive disorder as opposed to a bipolar disorder, and antidepressants alone usually don't have great results with people that have bipolar disorder.
Since you're presumably taking it for anxiety, I'd talk to your psychiatrist about other good anxiety meds. Explain how your symptoms have worsened. Hopefully you'll find a good medication for you. Good luck!