Although paradoxical responses to medication are not unheard of (exactly opposite reaction to what one would expect, like excitation from a benzo), I wonder if you're not experiencing withdrawal from the tobacco. There are a number of psychoactive compounds in tobacco smoke, not just nicotine. One effect is to block MAO-B, so your body may be producing too much MAO-B (rebound effect), leaving you vulnerable to stress. Try eating some dark chocolate, and see if your symptoms seem to remit.

Lar