I've been on tramadol (ultram) now for about a year and a half for pain related to endometriosis and I find it highly addicting. I crave it even when I don't need it. If I don't take any after using it for weeks in a row, I get jumpy, nauseous, and irritable.
Have you recently increased your dosage? Ultram has a mild antidepressant effect but you could be having the opposite reaction.