Definitely talk to your doctor.

In my psychopharmacology class, we learned that a lot of times SSRI's have the unfortunate effect of working for awhile, and then just stopping. I have seen this happen in regards to Lexapro with a couple of people.

But of course there are a million factors that might play into why you are feeling more depressed and anxious. Perhaps a dose increase is what you need-- talk to your doctor.