Back on this meds for anxiety???

After finding I just could not tolerate Sertraline without lots of back up meds, I just could not obtain from my GP, he has put me on Amitriptyline again at 20mg a night. Does such a low dose work at all? I only slept until 3am and have had to take 1mg of Lorazepam today I got so panicky. I know lots of people who have been prescribed Amitriptyline for anxiety but at what dose does it normally become therapeutic? On average. I'm not scared taking this meds like SSRI's so don't mind going up and up and up. But my last two AD's have not even worked (Escitalopram max dose and Mirtazapine all doses tried.)
I know this is a not so used meds nowadays but if anyone has had any luck with it, I'd love to hear from you. No side effects after day 2 so far, not even the dry mouth. Or is that bad thing as I once got told if you get side effects it means something is happening and the drug will work but I had them with the Lexapro and honestly, it never touched my anxiety, in fact it made me depressed and it's GAD I suffer with not depression.