Messed Up Everything

Hi [16M] here, I was a bright Student till Standard 8. After that I came into class 9 and made some amazing friends. Our group wasn't too big, just the 4 of us. I have distanced myself from the 2 of them because of some conflicts. So now I only have one friend. Also, I'm in an amazing relationship with this girl I met in class 10. Now coming to the issue, I passed my class 9th and 10th class with good marks without putting much efforts. I wanted to get into IITs after 12th. So my dad sent me to Kota. He is a very supportive of me. But that's where I messed up. I don't know how did I spend two years procrastinating. But it's true. I did not study anything at all for 2 years. I basically wasted 2 two years of time doing nothing. When I came home to appear for JEE Mains and Boards I knew I didn't know anything but still I sat in the JEE and scored 20 something percentile and I'm in similar condition in boards. I have given Physical Education and Physics Examination and both went horrible and upcoming are going to be even worse. I told everything to my dad and he said "koi baat nahi, hum hai na tumhare saath". I basically told him that I messed everything up and now I want to restart. I told my Girlfriend the same and she also comforted me and said she's gonna be by side no matter what. Everyone around me is so great to me. But I know that I've disappointed them. I've disappointed them multiple times. Now I want to fix everything. But don't know what path to chose. Earlier I was thinking of going back to Kota and joining a dropper batch. But that friend of mine told me not waste more money as it would cost a lot for that dropper batch [1.78 Lakhs] and also chances are I might not be getting good teachers teaching my batch. He suggested me that I should get a tablet and study online from home. But I don't like that idea. I don't wanna stay at my home. I wanna stay without a supervision on me so I prefer staying out of town. I'm thinking that I move to Kota but don't get enrolled in Allen but get some online courses and study by myself. I have to Cover Class 11 & 12 while preparing for boards, JEE MAINS & ADVANCED. [Yes, I'll be appearing again for boards] I know these seem like mountainous things to achieve but I believe, I can. I'm looking forward to you redittors suggestions, what should I do? If you suggest studying online, what teachers should I opt for. Thank You In Advance.