I haven't picked up my tobacco pipe in about exactly one week and I've had a bit of frustrated feelings a time or two, but by and large it's been pretty painless so far. I do know about panic attacks though, for many years I took care of a loved one and when she became bedridden and I had to take care of everything that went into and came out of her, it got sort of rough as I really didn't have a break for years, was always on call. She's passed about two and a half years ago and I'm just now feeling sort of normal again.
With the e-cigs, the main ingredient that's addicting is nicotine I believe so I would try stepping up the strength a bit and please do stick with it, I can already feel like it's going to be worth it, I mean I feel better in only a week!