Struggling after a major mistake and feeling disconnected

Assalamu alaikum, everyone. I'm reaching out because I honestly don't have anyone else to confide in. I'm a born Muslim, and lately, I'm drowning in regret after something I did. I went against my deen, and now I'm just overwhelmed with guilt. I always promised myself I wouldn't cross this line, but when it happened, I broke down crying and felt so much shame right in the middle of it. It was like I wasn't even present-almost like I was watching it from outside myself. I think my need for dopamine played a big role. I grew up with undiagnosed ADHD and autism, so I was always chasing thrills-from overeating to drinking and smoking later on. I recently got diagnosed with ADHD and told myself I'd quit those habits once I started medication. And I always held onto the belief that my body was precious, that I wouldn't commit zina. I asked a friend if we could do something sexual, and he said yes. I knew what I was requesting, but I wasn't ready for the aftermath. I thought I'd be fine, but instead, I feel filthy, used, confused, and deeply guilty. The spiritual weight is crushing. I'm scared I've damaged myself forever and that Allah won't forgive me. I know tawbah is real, but my heart is so heavy, it's hard to believe I can recover. I'm far from a perfect Muslim. I'm also stuck on this idea of virginity-did I lose it? I don't want to fixate on labels, but it's bugging me. I'm not here for judgment; I'm already harsh on myself. I need real advice from Muslims who've messed up, sincerely repented, and healed. How do I handle this guilt without it destroying me? How do I make sincere tawbah and move forward without replaying the incident? And how do I stop these impulsive actions from happening again? Please be gentle; I'm barely holding it together.