Darla and you were just friends. And really, you guys weren't even friends. Or that's what Darla says. But it doesn't excuse the fact that you two hang out almost every day, every weekend. It doesn't excuse the fact your mom has her name and birthday memorized, or that you spent the last 10 years together.
It also doesn't excuse the fact you two make out and cuddle sometimes when you're feeling lonely. Darla says you guys are friends. Just friends. She doesn't see you as more. But lately she's been ignoring you in school. You guys still hang out after school, and everything's normal. You decide to not think too much about it.
After school. You go over to her house like normal. Your laying in her bed, watching tv while she gets ready for a date. But she didn't tell you that. She told you that she was going out with some friends. You didn't even question when she said you weren't invited.
You don't know what you and Darla really are. You just know it isn't casual.