The fact of the matter is, sessions can complain about it all day, but they really have limited options in terms of realistically "doing something" about it.
It is worth noting that arguably their BEST case scenario in terms of shutting down the legal regulated markets could and quite likely would result in legal states reverting weed to a free-for-all status; (in addition to taking a massively unpopular political hit, so to speak, not just from our party but a lot of Republicans as well)- no regulations whatsoever. And it's not like forcing weed onto the black market stopped it before, only now there would be zero enforcement coming from the states in question.
It is that decidedly unappetizing prospect, from the feds' perspective, more than Obama having been an enthusiastic pot smoker in his youth- that drove the cole memo, I think.
And it is why despite making a lot of noises about it, Sessions is probably going to leave the thing mostly intact and alone.
In the meantime, maybe look into a weed vacation. I hear the opportunities for tourism are great, and our states sure love the $$$