I quit with Thrive lozenges, no probs whatsoever and I'm a huge stresscase sometimes. Didn't usually have one in the gym, maybe once or twice. No weird feelings, rapid HB or "buzz" feeling even during cardio.
I switched to the 1 mg pretty quick about half way through (6 weeks or so)
Finished the lozenges in 12 weeks, been smoke free for five mos. now.
good luck
(tried nicorette B4 but it hurt my jaw too much)