I smoked for over 40 yrs. (since I was a teen). Had no desire to quit. So bad I'd wake up at night to smoke & often fell back asleep w/a lit cig.! Thoroughly addicted to smoking. I tried the "accepted pharmacy products" that fail for most people (that's why it's still on the market!) w/out success. The ever-rising price of cigs got me thinking about quitting, but I was too hooked.
At a mall there was a kiosk selling the new e-cigs, when they were rather expensive. A major selling point for me was that you could use them anywhere (even on planes!) w/out a hassle - that was short-lived :-( . Anyway, I decided to try the (Green Nicotine) e-cigs. But I didn't stop smoking. I was getting the cheapest, nastiest cigs available. That helped me a lot!
As "vaping" became more widespread, cheaper, & more accessible, I got more into it. I vaped & smoked at the same time & therefore didn't feel like I was forcing myself & getting all stressed out about it. I started realizing that vaping tasted & smelled MUCH better than reg. cigs., & much less $$. It was a natural progression that worked for this cig. addict. NO stress, NO feeling like a failure, NO dwelling on it. What you're doing is "re-training" your brain, even if it takes awhile.
I didn't tell anyone (including myself) that I was trying to quit - just cut down a bit. I had to "ease" my brain into another way of thinking, for as long as it took, or my brain would rebel fiercely. I ,too, have mental health issues - anxiety & depression. Easing into it gently & privately didn't cause the anxiety to flare up.
Every once in awhile, I take a drag off a friend's cig., & it reinforces how nasty tasting & smelling they really are. It doesn't make me want to take it up again. No more burn holes or waking up to smoke either -what a bonus!
Don't set high expectations. Don't find fault in yourself if your brain just needs some time to adjust to a different source of nicotine. If necessary, talk to your doctor about prescribing a limited amount of an anti-anxiety medicine, if it doesn't exacerbate your mental health issues.
I find that stress, anxiety, & dwelling on it is counter-productive. This is also true of cancer. When I was told that I had breast cancer, I took it in stride, did what I had to do, & didn't freak out about it because that makes dealing w/ it much harder. I saw proof of that every time I went in for chemo. & radiation.
If a weak willed, totally addicted, & anxious person like me can do it ANYONE can! Experiment & find what works for you. Everyone is different.