Can't do anything in my life and i dont know WHY

please help i asked a question a year ago and asked many people and doctors. I can't focus on or finish any task if it's not urgent or exciting. I don't know how people could make movies, games, etc. over the course of years. I can only do something in one day if it has severe consequences by an authority figure or if it's easy and excites me and i rarely get excited. I can't be consistent. I could never focus on math no matter how hard I tried, I passed the entirety of middle-high school studying on the last day before deadlines. I tried many study techniques and timers and I can't push through the brain fog, Im NOT looking for study advice. People told me I'm bipolar, ADHD, or have anxiety, many doctors have told me/diagnosed me with ADHD. IM TIRED of this so ****ing tired. I do not have ADHD i do not have any of those and Im absolutely not a procrastinator. I'm cursed because I need adrenaline to do anything. I need the possible science or the reasons behind this please help.