Yes its normal to not dream that much or at all if you smoke much. I have noticed the same, if i smoke daily, i very rarely dream(or remember them), but if i stop smoking, for a few days i see very intense dreams that i remember very well usually. My friends have said the same thing.
I have been looking into this a bit and found that it seems that THC reduces the time you spend in REM sleep, which would explain the reduced dreaming. I dont think this is optimal for brain function for long time, so i have been looking into some remedies to combat this without having to stop smoking weed.
What i have found is that CBD counters this effects of THC if you smoke some CBD before going to bed. It also helps you to wake up faster and in case you got too little sleep, it helps to make that too short amount of sleep feel as if it was a bit longer sleep.
Another thing i recently noticed is magnesium supplement. I have not tested this for long, just a few days and i can definitely feel my dreaming going back to normal, despite smoking pretty much. I did know prior to trying that magnesium could have this sort of effect, but after having 2 nights where i dreamt a lot and remembered the dreams, i started looking if the magnesium supplement i got could have something to do with it, so i googled. I found many people saying that they had very intense dreams after starting to take magnesium. Then i looked a bit on why this could be and found some studies saying that it helps with same areas involved in memory formation as CBD does. Magnesium is essential to us humans like it is for plants, basically for similar stuff, carrying other things like potassium which are used as a building block for many things in your body, including brains. Zinc is good thing to take with magnesium.
Im sure there are also other things that can also counter this side effect of THC.
Also if you smoke weed, its good idea to have more antioxidants than normal, because they are needed in removing the free radicals caused by inhaled smoke and its carcinogens. But that doesent really have anything to do with sleep, but just thought i would also drop this little tip also.