Hi Murphydog,
well, the first reply, was maybe just about as serious as your inquiry itself? (imho)
But seriously,
some people, need a beer or two to take the edge off. Alcohol is legal.
Nicotine is legal.
You need nicotine, and you are getting it in a way that is healthier than real cigarettes. Okok, so i can't prove this, nor anyone at this point - but go ask your doctor, and if he does't have his/her MD shoved so far up their a$s, then im sure they will tell you, vaping is better than smoking.
Addiction is generally a "bad" thing, ... and so addiction to let's say the previously mentioned alcohol or nicotine would be considered "bad" and thus your "guilt". But really, who out there is totally not addicted to something ... whether it be a bad tv series, 2 uncaring friends with benefits (or 10), online gaming, potato chips, doritos, oreos, or . . . .
Maybe you are not addicted and you need nicotine for this period in your life to keep your psyche stable.
You've quit smoking in the past, however, you have found some need for a little "something" now to keep stable... and instead of smoking you are vaping. Less smoke, less toxins.
What me worry?
If you still feel guilty after this rant, then try vaping 0mg juice. Maybe you aren't so addicted to nicotine itself, and just really need the action to help "smooth" you out. Nothing wrong with keeping a hobby to smooth out the nerves.

Happy Vaping and Be Healthy!
I gave up smoking 20+ a day over nine years ago, I really don't like the smell of a cigarette so would never start back, but have had a lot of stress lately and needed something, so last week got an evod kit and have just brought a protank2.
i have started on 6mg juice and have feel no need to increase this.
Should I feel guilty as I'm really enjoying it.