It's hard for me to relate to this. I smoke daily, and probably what most would consider a lot. I however also travel for work and or other reasons and often go days or a week without smoking. It has no noticeable effect on me.
It could be because I'm extremely active and fit. I workout basically 7 days a week, mostly because I do a lot of intense stuff 'for fun' (aka, play hockey 3-4 days a week, etc).
I'm not saying it's not true, just pointing out this could be related to things beyond just pot. Aka, inactivity, perhaps an already down mental state, etc etc.
I also take a shit-ton of vitamins and sups, I'm about to turn 51 and I train hard and play hard because I'm often skating against high-level 18-20 year old's etc, so I'm quite driven to stay at the top of my game. Possible some of the vits/sups I take are offsetting whatever the pot is doing to others.
Diet, exercise, sleep - so many factors goes into feeling well. Addiction though, man that's a lot more extreme than I would label my desire for pot. I mean I certainly enjoy it and even sometimes wish I had some on a trip, but it's a passing though more than anything.
Update: one point I should note, I only smoke Sativa's, or sativa heavy hybrids. Not sure if that's a factor but thought I was worth noting.