I was going to ask about it, but you opened up more.
Since you no longer just want sex, the direct approach that could pressure her sends the wrong message.
She appears to be having a good time with you and wants to keep that. I suppose so do you.
Therefore, being casual is the most practical way to approach her.
The self-loathing message was a mistake. You want her to enjoy your time together, and that's not possible if she starts to pity you.
You'd want her to know the real you, so don't bother trying to create a facade that covers up your insecurities. Make her feel comfortable around you. If she interprets your messages as an attempt to control her free time by not caring about talking to each other, she will close in. I believe that getting straight to the point (to meet and have any kind of activity) in your early conversations may halt this procedure to the point of you appearing creepy. If you no longer want to just have sex with her, place yourself in her shoes.
If you get out together, I suggest being honest with her. I would make a shy fool out of myself, explaining that I really like her, and that's the reason some of my messages appeared a bit too weird (uncomfortable laugh). It was just a way to approach her without seeming too clingy or w/e.
Everyone has their style of flirting, but you ought to bring your b-game (if too nervous for the a-game) in your next encounter.