Alcohol was like that for me. Try going without for a good amount of time (you'll figure this out with practice) and you can reset that.

I don't drink regularly anymore so now if I have one beer I have a nice buzz going.

Of course, if you can't function without the weed do only what works for you! I'm just talking about resetting the tolerance but most people already know about it but every once in a while someone might learn something new