I got arrested for marijuana possession, I need advice.?

I was arrested yesterday for marijuana possession. I was smokin a little bud with some friends, then we all went out for a cigarette afterwards, then the police show up, I got arrested because of a "concerned neighbor - aka this mean old lady across the street". However, I was wondering what some possible good legal advice would be because I noticed a couple of things that were slightly, crooked, about this pig.. er uh i mean "police officer". When my dad came to pick me up at the police station, the police officer told me that they scaled 4 grams on me, I KNOW there was NOT 4 grams there, I told my friends I wanted to save enough for one bowl for the morning, that is nowhere near 4 grams. The second thing I remembered today when I woke up was, when I got arrested yesterday, the police never read me my miranda rights! So, basically, any good legal advice would be appreciated and any information about what's going to happen to me, oh and as a side note I am 17 years old and was arrested and live in indiana.