I FUCKED UP , PLEASE HELP!

So basically in Dec 2023, in my coaching there was a girl who liked me very much and I had no idea , we talked for few weeks and she confessed, I was not having strong feelings for her but kind of bored so I agreed. We started dating, things happened , I tried to connect with her so I LIED ABOUT MANY THINGS , FROM HERE THE SHIT GOES REAL BAD she had a pet dog and loved her , so I lied to her that "oh yes , I had a dog too... But he died sadly" , it worked and she was really effected by this One day she told me about losing loved ones and the consequences, me being an absolute idiot just trying to have fun and time pass , I lied that I lost a brother in an accident, she got very close to me and effected by that A MONTH AGO , she asked me about my brother's age and I forgot what I told her previously , it was 19 and I told 30 , Then she realises Everything was a lie and she broke up , sobbing heavily on calls I AM EXTREMELY GUILTY AND HAVE F REGRET FOR WHAT I DID i know I did very wrong but I loved her alot , please tell me what should I do, I was just having fun in the beginning but now I miss her