Hello and hope you are doing well.
Insomnia is a side effect of Amitriptyline. But you may develop tolerance to this effect. However if it persists, discuss your symptoms with your consulting doctor he may change the dose or the medications.
Hope this helped and do keep us posted.
I just read this about Endep:
More common side effects include dizziness, drowsiness, fatigue and delirium... and in rare cases, seizure.
Could the reason I am having these strange feeling and light-headedness be because the the Zolpidem which put me to sleep be out of the equation? I did feel the light headed feeling when I was also on Zolpidem but the Zolpidem did put me out to sleep.