my best friend was molestedin front of me, police involved

I need help.

last weekend me and my two friends taylor and gab went over this boy, jons house. he had another friend, josh with him.

everyone was drunk besides gab. josh was all over gab. he was putting his hands on her and touching her when she didnt want him to. they went on a walk while everyone stayyed at jon house. When gab got back we all just layyed on jons bed and watched tv. because I am not friends with jon and josh I wasnt really talking to them and they didnt really do anything to me. jon was all over taylor but taylor was all over him to, I was right there and did not see or hear her once tell him to stop. taylor is also known for lying and spreading rumors and has a big mouth. I was just on my phone talking to my boyfriend and texting watching tv not really paying attention to anything. I herd gab tell josh to stop. and he didnt so I went over there and I yelled at him to stop and that I was serious. then gab pulled me in the bathroom and told me what happened. josh had pulled down her shirt and sucking on her boob. he also tried to stick his fingers up her vagina through her pants and that he kept trying to kiss her and kissing her neck and everything. she said she didnt want to be there so I called my boyfriend to pick me up and he cant drive yet so he had his friend pick us up to bring us to my house. gab had also said that jon was touching her to, I forget exactly what he did but he did things to to her also. taylor had mentioned that jon had fingered her and stuff but me and gab do not believe her since we didnt hear her stop

today at school EVERYONE found out. people we dont even know are coming up asking about it. gab is very embarresed she said tha tpeople are adding her on a social site, coming up to her in the hall, asking if she was the girl who got raped, when she didnt get raped she got melested…we had told our friend who is a senior what happened and he cares for gabalot so he was pissed. at lunch he went up to jon and josh and started screaming at them calling them sick and punch the vending meachine and left. he got sent home after that. at the end of the day gab got called down to the deans and now the police are involved.
I told my mom what happened so I could stay home with gab but I didnt let her know that I was drunk or they were drunk I told her that josh annd gab went on a walk it happened which they did but I didnt want her to know I was drinking.

I dont knwo what to do. what if I get called down to the office, what do I say? so I tell them I was drinking, will I get introuble if I do? I know it was long but this is serious and I am clueless. I feel like total crap because I have been molested before and it was terrible and I was there when it happened to my bestfriend and I didnt do anything.