An inference is a conclusion made based on evidence
"Your having the best day at school nothing could put you down, well that’s what you thought. You come home to your laptop logged on to face book where that same person last week had chatted you and now is commenting on your photo mean, nasty comments."
Based on the text, I can infer that this has happened to this person before because they explain the what it feels like.
"There I was... laying there silently in denial. Thinking maybe if I close my eyes I would be back where I was the night before when I opened them back."
Based on this text, I can infer that this person just went through a life changing experience or is regretting something because they want things to go back to the way they were.
"My school has began a new campagin aganist bullying, so there have been anti-bullying posters plastered all over the walls of the school like the ugly wall-paper on the walls of my garndma's livign room. Both are probally equallly effective in stoppign bulllying."
Based on the text, I can infer that that this person has been bullied and is convinced that the posters won't help.