Well, I'm sort of going to agree with the poster who said your meeting your girls in the wrong places (paraphrasing here).

Seriously, try meeting a girl while you're sober. And she needs to be sober as well. Get to know each other, fuck like rabbits (all of this taking place over more than just a day or two AND sober)... then after you get to a point where you figure out if you're really into her, and she's into you, then toke up, take ex, whatever.

I'm not trying to ruin your good time or anything like that, but if you want something long term and serious, and want to be in love and stay in love, then it has to be based on more than just a party where you both met while fucked up on something. Otherwise what your doing is going to keep on happening. You'll keep waking up the next morning and think "who the fuck is this? I felt like I knew her..." Because she's thinking the exact same thing about you.

Good luck, you deserve it.