I have not read the whole thing, because it's very long and doesn't have nearly enough paragraph breaks. Plus, it appears to have been cut off before the end. But here is some advice based on what I did read.
1. The dialogue isn't believable. It's transparently calculated to have a certain effect on the reader, either to evoke an emotion or to lead their train of thought in a certain direction. But it's not what real people would really say in such a situation. Try this: whenever you need a line of dialogue, imagine yourself in the character's situation, speaking to people you know, and ask yourself what you would say, if this were real. If the role is too much of a stretch for you, then imagine what your mother, or your best friend, etc., would say.
2. Many of the sentences are run-ons. As an exercise, try going through and chopping up sentences so that each one contains only one or two clauses. (A "clause" is a part of a sentence that has a subject and a verb and could stand on its own, grammatically, as a complete sentence.) Here's an example:
“I’m not feeling that good today…” I lied, the real reason was I wanted to see the mysterious note and I kept imaging what it would be, maybe a girl liked me or maybe Tony was in trouble, I didn’t know but I didn’t want to do work at all.
“I’m not feeling that good today,” I lied. The real reason was that I wanted to see the mysterious note. I kept imagining what it would be. Maybe a girl liked me, or maybe Tony was in trouble. I didn’t know, but I didn’t want to do work at all.
Shorter sentences are easier to read, and in a suspense-driven story like this one, they can also help to establish a tense, quick-moving atmosphere.
The what mentioned above is total fiction. Please don't take it seriously!