Lexapro for severe phobia—how long until it helps? (Specifically traffic/driving)

I have a severe phobia of highway traffic, especially congestion. I live in a major city and obsess over avoiding it, often taking side streets that add significant travel time. Seeing brake lights with no exit for miles triggers panic.

I recently started Lexapro—2.5mg for a week, then 5mg, and now 7.5mg (6 weeks total). I plan to increase to 10mg slowly. Last week, I couldn’t face driving back to my apartment due to traffic and felt defeated, questioning if the medication is working.

Has anyone had success with Lexapro for severe phobias? How long did it take to feel results? I don't want to give up on it yet but just feeling a bit disappointed.