It's natural you feel like you're in a pit now. But the only way to get out of this pit is to stop contacting her AND following her! Believe me, this feeling WILL pass, but only if you're resilient enough and enforce some discipline on yourself. Please do not get me wrong, I'm not trying to be hard on you, but you need to recognize that your number one priority now is yourself, and how you can free yourself of this obsession of her.
I'm sorry to say this but, despite all that you've described, I think she only wants to be a friend. Women who wants more doesn't act in the manner that you've described. Was she leading you on? Yes. Maybe. A little. But you let her.
Now, don't do this to yourself anymore. Stop thinking about her and move on.
And oh, tell yourself this.... she passes you by, it's her loss. Good luck