Is it the immediate release one or is it XR. Do you take it more than one time a day. I had the immediate release one at first. I took it 2 times a day as needed. I had these symptoms when it started wearing off and then I would take my second dose if I needed it for that day. My doctor had discussed with me that the immediate release one dose have that effect when it wears off. The increasing anxiety and I would start kinda shaking or shivering like when I have increasing anxiety but it would go away after some time of my body adjusting. I changed to XR version because it doesn't have those effects and plus it's easier based on my daily schedule to take the one in the morning when I wake up and just go about my day. I don't need an immediate release based on my current schedule.