Need help with my low self esteem

[iGuest 3]

Hey guys, im currently in grade 11, a critical stage of highschool since I only have one year to go. In grade 7 I used to do great in my academics, like i was always the top student in class. But when I got to grade 8 I had the worst teacher of my life, he was always yelling and always gave us pressure. After that year I started to slack off and get lazy, like the slack was more like who cares? when really I do care? Im not doing that great academically right now. Like i really want to start working hard, get motivated, and acheive success. I am a person that has an ambition i strive to acheive everyday. I feel like I have no motivation, its very hard to self motivate myself. And im having problems being comitted to achieve goals, everytime i plan to do something, I get distracted from something else and I forget doing what I planned. How do I self motivate myself? I try to look for inspiration but i cant really find anyone that strongly inspires me. I really want to get focused in my goals and work but I get withdrawn so easily. and lately Ive encountered issues like getting bullied and its affected me emotionally. I have a positive attitude now, and i really really want to start improving in school. Can anyone please give me good suggestions? I would accept & appreciate any suggestion given. Thankyou