This is typical, I've experienced a lot of this myself. Look at the information she's told you. You're not more important than a night at the bar... You're not more important than anything else going on in her life. She can't commit to any plans with you... You're not a priority and she's not really that into you.

More than likely... She's just lonely, and using you for free weed and companionship. You're more of a friend with hardly any benefits. Obviously, you're not satisfied with that.

You need to be less available and retract. Don't be cold, just don't try to hang out with her anymore. If she texts you just ignore it. If she brings it up at work just tell her you got side tracked and forgot about it. If she gets persistent, tell her you met a new girl online and want to see where it's going. If she starts asking to see her etc then just tell her you aren't sure about her yet.

Surely to goodness she'll get the hint by then, but if not, you may eventually have to just tell her you're not interested anymore.