Antidepressants are often very effective at controlling anxiety and alot of people taket them just for anxiety. Lexapro is one of those that is known for that. You may not want to hear this, but 5mg is not very much. It's not even considered the lowest therapuetic dose. Paxil is another, but I would never take that. The horror stories of trying to get off that stuff are unreal.
You say you arent depressed but the simple fact is if you keep suffering from this anxiety long enough, you will be. Anxiety and depression go together like peanut butter and jelly. You need to get it under control NOW before it spirals downward. Are you in any type of counseling?