How addictive is Tramadol ?

I have been taking Tramadol (and neurontin, flexeril, and vicodin) for quite some time for nerve damage, fibro, and lower back pain.  At my last vist to the pain clinic, the guy working at the front desk pulled me aside and warned me that tramadol was addictive and I should be careful about taking it.  He said he and his wife both took tramadol after a car accident and that they had really bad withdrawl symptoms when they stopped the drug.  I have noticed that If I am late taking my pills, I start to sweat and even shake a little.  That and the most weird sensations in my legs - like electrical currents coursing down to my feet.  This is scary.  Anyone have some experience with this?  I would appreciate some input.

Thanks

Jeff