I've had times at wich I thought was pretty immune as well
I smoked a lot of weed back then, was stoned pretty much all day for a long time.
It became normal, it felt stranger to be sober (wich I actually never was)..
Now I only very seldomly smoke cannabis, sometimes months in between.
I have gotten extremely sensitive now, so sensitive that after a few tokes I'll be pretty damn stoned/high and my brain will be shaken for the day after quite a bit as well
But then again I feel like weed here is still getting stronger and my friends have the habit of buying high thc weed.. super white mystery, amnesia.. too much for me now :?
Try quitting a few days and then roll a fat pure blunt or make a tulip in a bong or sth is my advice
Or maybe you should try smoking a different kind of weed/hasj, possibly with a higher THC percentage
If you've done both of these and still don't feel anything I say you can consider immunity though I think of it as highly unlikely..
But suppose you are immune, as mentioned already theres lots of other nice highs.. try kratom or sth
