Hello and welcome!
I am sorry that you are experiencing possible inefficacy with your Lex...I know this is frustrating and confusing. However, three years isn't a very long time to be on an Rx, so I definitely think that trying an increase before anything else is a good plan. I like the idea of going up slowly...to 17.5 for some time and then to 20. I think that gentle increases/decreases are the way to go with SSRI's.
Are you currently also practicing coping skills to round out your management program? The more tools you have at your disposal the better of course. If you need some fresh ideas, be sure and see our Resources at the top of the main forum page here for great material.
Keep posting with us as well if you find it helpful. We understand and support is key! We'll be here to keep you encouraged through this challenging time if you'd like.
"Courage is not the abscence of fear, it is feeling afraid and doing it anyway!"
"Worrying does not empty tomorrow of its troubles...it empties today of its strength."
Corrie Ten Boom
Panic Syndrome recovery due to CBT