It's possible you are craving something besides nicotine. Try adding snus to your day. I recommend Swedish snus but if you can't get that, try Camel snus to get you going. I wasn't trying to quit, just trying to save money, and continued to smoke analogs for months after starting to vape. My smoking went WAY down, but not completely. When I just vaped I went kinda crazy--depression, confused thoughts, etc. Reading the "are we getting it?" thread made me realize I needed the MAOI's, too, so I got some snus and tried it. Hated it at first (the bulge in my lip was strange) but stuck with the mini's (General mini mint is a good one to start with) and now I don't even notice they're there. They give me the extra "something" I just had to have. So now I haven't smoked since May and that's good, but I couldn't have done it with just vaping (at any strength). I use about 2-3 mini's a day in addition to constant vaping and it's still working.
In addition, I believe my own success was due to a large degree because I WASN'T TRYING TO QUIT SMOKING. There's too much pressure for me (after so many failed attempts) in that, psychologically. Just THINKING about quitting makes me so anxious I need to smoke two cigarettes in a row! So I repeat the mantra I heard on this forum so many times: It doesn't matter how many you smoke. Keep track of how many you AREN'T smoking and congratulate yourself and cut yourself some slack.
Good luck--and try some Swedish snus!