I had to do an assignment with a classmate and everything was fine until we started to work. We couldn't plan almost anything together and, as she was working and didn't had much time to do much, I offered her to do the assignment on my own and she accepted. After a few days another classmate asked me how we were going and I told her that the other girl had left me to do everything on my own. Some other people asked me the same and I lied them too. Then, some weeks later, closely to the due date, the girl asked me i I had given the assignment to the teacher and I said yes, which was a lie because I was on the middle of it. A few days ago, I said her I've given the wrong one (while we worked together we made some form of assignment which was very short). The problem is that now she has the full assignment and I'm at home sick. I don't know when I can go to university and I'm afraid the lies will become clear and we will both suffer a punishment. I genuinely feel bad and I want to save both my reputation and her. What can I do?