My mother doesn't understand?

Im a teen, just going into highschool. Summer just started, and I did something during the first week of summer. I told her I was staying at a friends house, but I really wasnt. The friend I was, "going" to said she was staying at my house, so it was flip flopped. We stayed out all night, and got drunk. There is a abondoned house on a street that we ended up staying at. It was already open, no one broke in.. I trusted my sister, so I told her what happened, and I gave her every little detail. Yesterday, my sister told my mom just because she wasnt allowed to stay at her friends house. Now my mom does not trust me at all. I already talked to my sister, and I know what I did was stupid, but honestly I do NOT regret it at all. But now I also know that alcohol could ruin my life, and I do not want to get addicted to it. I know the consequences of this, and I understand that I shouldnt do it anymore. BUT; It was the best night of my life. Now im grounded, got my phone taken away, and my summer is ruined, because now I am not allowed to hang out with any friends. My mom also keeps telling me that im a disappointment,and that im a shame. But she tells my sister to "apologize" to me for ruining everything. Im so confused, and honestly I do not know what to do. Im not talking to my sister because she ruined everything for me, and I do not like her AT ALL. I just want a opinion on what to do, I dont want anybody telling me how horrible I am or some stupid stuff like that. Just help.