I Didn't Mean It (sequel to It Was an Accident)

Derek

Derek thought about running after him, following him home, begging him to stay... but he knew, as much as he hated to admit, Stiles would never forgive him. He was angry, but only at himself. He made the mistake, he kept it from Stiles, and he let Stiles go. The only thing left for him to do was hate himself and stay in bed forever. That was the plan. Or, it was the plan, until Erica burst through the door without knocking and started yelling.

"Derek Hale is not a quitter!" she started, grabbing his arm to force him to sit up. He groggily rubbed at his eyes, staring at the ground in embarrassment. "When I bet you couldn't finish the ten page essay in one night, what did you do? Not only did you write it, you also got an A on it! And what about that time Boyd said you couldn't finish off the bottle of vodka and you drank it straight, nothing with it. You may have thrown up afterwards, but you didn't quit. Because you, Derek Hale, are not a fucking quitter."

"I lost the most important person to me," Derek whimpered, pressing his hands into his eyes to stop the tears. "I broke his heart, and why? Because I was feeling a little lonely. Because things were just a little hard, I fucked them up even more and ruined the best thing that ever happened to me. I think it's time I become a quitter, Erica."

Erica grabbed his wrists, yanking them away from his face to force him to look at her. "No, listen to me. You messed up, okay, big time. But here's the thing, Derek. Stiles loves you. If you try, and I mean really try, maybe you can get him back. Or, be a quitter and you'll never see what happens. If you ask me--" she started, but was cut off by the door swinging open again. Immediately, Derek's stomach dropped.

"Fuck," he whispered, trying to scramble out of the sheets. "Lydia, I'm so--" he tried, but she slapped him in the face before he could finish. He quickly covered his face at the stinging sensation, gritting his teeth. "Alright, yeah, I deserved that."

"Yes, you did," Lydia spat, smacking his arm this time, not as hard. "What the hell is wrong with you? We are supposed to be best friends. Why didn't you call me before screwing up this badly? Stiles is a mess right now, and probably will be for a while. He's not going to be able to get over you, but he should, because you're an asshole, Derek."

"Okay, you can't just come in here bitch-slapping people!" Erica yelled, trying to intervene.

Lydia put herself between Derek and Erica, her hands on her hips. "I don't know who you are, but-"

"I am Derek's best friend," Erica said matter-of-factly, which made Lydia snort. "What?" Erica demanded, raising her eyebrows. Derek knew this could get ugly and he wasn't in the place to deal with a catfight.

"That's cute," Lydia said with a fake grin. "I am and always have been Derek's best friend, so while you may be his buddy here at college, this situation is in my hands, not yours. I know Stiles and Derek,  so let me handle this."

"Guys," Derek sighed, pulling Lydia by her arm off to the side. "There is no situation to handle, alright? I screwed everything up and Stiles will never forgive me. Just let me sulk and think about how much of an asshole I am." He turned around and fell back into bed, burying his face in a pillow. There was a long period of silence before Derek turned his head to see both girls staring at him, arms crossed. "Please go away."

"No," Erica sighed. "You need to fight for him. You screwed up, but it might not be the end."

"She's right," Lydia agreed, unwillingly. "Stiles has skipped school the past two days and I even bought him a whole pizza from his favorite place that he didn't even touch. He's in so much pain, Derek. Maybe you have time to win him back, if you really try, and convince him you love him, that you'll never do it again..."