What did I do wrong? Please help me get out of this..?

My friend got caught with marijuanna on her (which I gave to her I'm not a dealer) and a pipe in school. She didn't rat me out to security because she likes me a lot but I think her mom beat it out of her and she called the school. Now at this point the school is thinking "okay let's suspend him and shut the mom up". They called me in and they asked if I gave her pot. I admitted to everything and was polite calm and patient. I figured they're only doing they're job why cause more frustration. Now instead of taking 10 minutes to ask me if I did it they waste time bringing a security guard in to search me ( I had a lighter and an empty pack of cigarettes). Then the school psychiatrist gets involved. Then the head of security. Then the school cop finnaly comes after 2 hours of waiting for him. He makes me sign a Miranda warning (Im 17 for Christ sake). He ends up Bering and even though I was nice. Now I understand that I was an idiot for getting pot but I didn't give it to her in school and I thought nothing of it. I had weed for a total of 5 minutes and gave it to my friend and thought that would be the end of it. But everyone was an hole. My mom is defending me for getting a 10 day suspension but my step dad is being an and doesn't care whats fair. So I'm grounded for telling the truth basically.. I reeaeanged my room and cleaning out the garage tomorrow. What can I do to help my stupid situation. Sorry I'm a nice stoner who believes highly in forgivness and good karma..Everyone see's me as an Antichrist at school and my step dad calls me a or a punk half the time..