Nicotine can be almost as hard to kick as heroin, I’ve read someplace.
I tried all the replacements, gum, lozenge and patch, and the antidepressant Wellbutrin. What finally worked for me was Chantix and the steps of the AA program applied to smoking.
It can be tremendously hard to quit and stay stopped. I feel for you!
Here’s a thread on the topic (I didn’t realize there were two threads in the series, this is the second)