I've been on Tramadol for three years due to chronic hip/back pain. I took my last dose Nov 18th and woke up next morning ill. I did not think of needing to taper of them because I did not abuse them. I was over all of it in seven days except for for the sweating or freezing. It's 28 days later and I am still either freezing or sweating. Is this normal? How long does that last?