For tooth975: TMJ appliance question?

Yesterday I got my TMJ appliance and it kind of looks like the most upper one in this picture a href="http://www.arroworthodontics.com/images/DSC01838.jpg." rel="nofollow"http://www.arroworthodontics.com/images/…/a I have a retruded chin, extreme overbite, popping jaw. and i have closed lock with reduction. When I wear the appliance, my bottom teeth hit this part of the appliance that makes them go forward. I'm supposed to wear them for about 3-4 months. My concern is that I'm unable pop my jaw out with the appliance in, which I am able to do without. My orthodontist said to keep trying until I am able to. I'm somewhat nervous that if I do manage to pop my jaw out it will get stuck and lock. Also another concern is that when I had my appliance in for a couple of hours, I get like a mini anxiety attack because I feel like there's a need to take it out (which I did.. :/) and tried to pop my jaw in place, which ended up it getting locked and for a couple of seconds before it unlocked When it unlocked my jaw started to click for a few moments. Should I just keep my appliance it and try to ignore my occasional anxiety attacks or should I talk to my orthodontist about it?