Now i know we all know that Sam fell off the wagon and started drinking demon blood. But there was a lot of time unaccounted for... So here's one thing that could of happened.

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Sam sat on the edge of the his motel bed, clasping his hands tightly as they trembled. He stared at his phone frantically, not understanding why Ruby wasn't calling him back. He needed blood, not like a vampire, but like a junkie needed their drugs. 

He had started noticing the withdrawal symptoms that morning, with the trembling and body aches. Shortly afterward he was hit with chills and heat flashes. indicating a fever was now raging through his body. 

"Damnit Ruby, I wouldn't have agreed to doing this if i knew I'd go into withdrawals waiting for your return." he yelled hoarsely, laying back on the bed too quickly. He groaned weakly, as the room started spinning rapidly and made it feel like his bed was a boat or spinning top. 

He threw his arm over his face, trying to breathe through the vertigo that was making him feel sick. After what felt like hours, the vertigo abated enough to let him doze off. 

After about an hour, he jerked awake to a cold hand on his forehead. 

"Damn Sam!" Ruby hissed softly, looking down at him in concern. 

"Ruby?" he croaked weakly, his cheeks flushed and eyes glazed over from the raging fever.

"Hey hotshot, I got your message... But this doesn't feel like a withdrawal. I think you're sick." she said worriedly. She had been a demon long enough, not to know how to take care of a sick person. 

She did know that he was feverish and sounded miserable, but she wasn't sure what to do about it. She did know not to give him any more of her blood, as it would make him feel even worse. 

"Really?" he asked in surprise, wincing as his voice grated against his sore throat. 

She flinched at his hoarse voice, wishing she could relieve it. She was a demon, which didn't give her the ability to heal illness or injury. 

"Yes, go back to sleep. I'll stick around until you wake up again." she offered gently, hoping he would feel better. She had a sneaking suspicion that he wouldn't be feeling better anytime soon. 

Sam shook his head head briefly, groaning as the pounding in his head increased harshly. He swallowed hard, feeling like his throat was swollen. His saliva felt like razor blades, earning a soft whimper from him. 

Ruby sighed softly, walking over and grabbing the first aid kit. She brought it back over to Sam's side, and proceeded to try to open it. What she didn't see was that there was a sharp object that cut into her finger deeply enough to bleed. 

"Oh crap." she mumbled, looking at her finger in surprise. Sam's eyes locked on the drop of blood running down her finger, and before either could realize what had happened he was sucking on her finger hard. He wanted... No he needed that blood, and he needed it now. 

He moaned in relief as the withdrawal symptoms stopped, but he hadn't expected the vertigo to return so suddenly. He pushed her aside as he doubled over, retching harshly. 

Ruby's eyes widened, as he rushed to grab a trash can. She placed it underneath him, just in time for the blood to reappear with a vengeance. "I could have told you this would happen." she said regretfully. 

Sam glared at her angrily, vomiting again. "Shut up, Ruby." he ground out, before vomiting again. HE felt at least semi in control again, which had been the goal. 

Present Day: Season 4 after Dean returns: 

Dean glared at Sam, who was now hunched over a bucket, regaling his brother of Ruby's kindness while trying not to lose the blood he had just ingested. 

"Why are you doing this to yourself?!" Dean asked angrily. 

"Because I wasn't strong *gag* enough." Sam said mournfully, as he gagged again and brought up all the blood he had just ingested. He was pissed now, but what was worse was Dean now knew his secret. 

"So drinking demon blood fixed that?" Dean snapped back, devastated to see his brother in this situation. He was pissed that he had gone to hell to begin with, and he was even more pissed that his dad had been right about Sam being on a track to something really bad. 

"Yes, it did." Sam moaned weakly, throwing up everything left in his stomach. He whimpered softly, looking at Dean with sad eyes. "I need it, Dean. You're gone and I am all alone." he said softly, tears pouring down his cheeks. 

Dean froze, looking at Sam in shock as he realized that his little brother was now hallucinating. "Sam, its me." he said firmly, seeing the younger man shake his head. 

The younger hunter turned away, throwing up again as he started throwing up his own blood. He had no idea what was going on, as he went limp, curling into a fetal position on the floor. Even curled up tight, he kept gagging up more blood, unable to stop. 

"Damnit Sammy! Ruby, get your demon ass here... NOW!" Dean yelled, knowing she was nearby. 

Ruby walked in the front door, looking at Dean solemnly. "You didn't summon me, just to kill me, did you?" she asked sarcastically. 

"Fix him," Dean said hopelessly. He moved so Ruby could see Sam. 

Ruby gasped, pulling out her knife and sliced her palm. She rushed to Sam's side, putting her cut palm to his mouth, immediately stopping the vomiting and the bleeding. 

Sam fell asleep quickly, no clue that Ruby had ever visited. 

"I was never here." She said quickly, before disappearing again. 

Dean nodded and sighed softly, as he waited to see what would happen next. 

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We all know how the real story ends, but i just gave you a little snippet to change that story. Lol. Hope you enjoyed it!