I’m on 10 mg Lexapro for 5 weeks. Anxiety is back and worse. Is this normal?

You should definitely speak with your doctor. He/she may increase your dosage of Lexapro, add a second anti-anxiety drug, or take you off Lexapro to try something else. You might even be advised to stay the course for a while longer.

Personally, I've had great success (so far) with taking 10 mg Lexapro after the evening meal, then 15 mg of Trazodone at bedtime.

Hi, Lemonade!
It's not unusual to be up and down while your metabolism is still adjusting. It might mean that you need to increase your dose.
Talk to your doctor and let them know that you're having this breakthrough anxiety and see what they have to advise.
Best regards and I hope you feel better quickly.