My hubby took this med and never had that reaction when it was increased. He did start feeling pretty sick after some time (he took it for years) and we weened him off and he's much better. Maybe it's not working for your pain anymore? He took it for neuropathic pain and once that was gone the med seemed to have the opposite effect on him.

I agree that maybe give the doctor a call. It could be you can't take the higher dose and you'll need to find another pain med.