Is this a good probable cause for a police?

Ok so me and 3 other body(3 of us freshman and 1 sophmore) got out of school. it was exams and it was 3rd to last day of school. We were all exempt from exams so we wern't allowed to come to school so we dont mess with the other testing kids. we were going to go hit the ganja. and please dont judge me, all 4 of us are A,B honor students. well we were leaving an alley and none of us were high. 2 of us had bookbags and 3 of us had marijuana. A police car pulls over and two men step out of the car. this is were i **** my pants. but the dick police guy ask to search the non marijuana carrier kids book bag. the kid ask what was his probable cause and the police said because he was acting nervous and because he had a bookbag. so the police pulls him over to the car and from were he was, we couldnt see him. well turns out he had a bamboo bong that was slightly used and a grinder slightly used. while the miget cop asked the 3 of us our information. they did search my bookbag but i had nothing in it, everything was in my pocket. well they called the searched bookbag kid's parents. and when they got there they took him home and he didnt get charged with anything. The dick cop came to us and asked us if we had any marijuana, and the dumb stoner of the group gave him a joint. the other kid game him a bowl and a 1g bag. and i gave him a packed bowl. The three of us were mad eto put our hands on the car and they emptied our pockets onto the car and they did the full search, the crouch grab and all, and they wernt nice at all except the new cop guy. we got taken down town and were charged to take substence testing and to serve this diversion thing. when i told my dad all this he thought it wasnt a good probable cause and he thinks the cop was taking advantage of us being kids. and while we were put in these small enclosed alarmed juvi rooms the cops were outside the room joking and laughing making jokes. my dad also thinks that the kid that was let go was only let go becuase the cops were afraid to be sued because of their bad probable cause reason, even though he had a used bong and grinder. and my dad is not stupid he is a 49 yr old hippie, he knows his stuff. my question is, do any of u think this is a good probable cause and what should I do.