Lexapro is an SSRI like Zoloft, Prozac, etc. Sometimes it can be a little trial and error before one finds the right medication in my experience. They all effect us in certain ways. With this, are you seeing a counselor? I believe the most important step you can take is to seek counseling and learn about your anxiety. Knowledge is power in confronting this...keep us posted!
You say you were taking Zoloft at 2Mgs a day? I didn't even know Zoloft came in such a low dosage. I used to take Zoloft at 200Mgs a day. Lowest dosage is 50mgs a day and even that dosage is too low for most people.