Is it normal to experience extreme fatigue when going on lexapro? started at 10mg and ive been 20 days on 20mg and im noticing benefits minus i am crashing mid day for naps. does this improve over time?

Yes, fatigue is one of the reported side effects. By Drugs.com: side effects have been reported to be generally mild and transient. They are most common during the first 2 weeks of treatment and decrease in intensity and frequency with continued treatment. They generally do not lead to treatment cessation.

Fatigue symptom is common after starting Lexapro and it usually gets better within couple of weeks or so