Even if you fail thousand times, you should make one more attempt. So don't give up and don't quit. Thomas Alva Edison was a school drop out. But remember he went on to make so many inventions. The entire human race would be grateful to him for this. Formal education was not a hurdle for his success. So my friend, don't worry if you forget things or feel sick. Its quite natural and many of us feel the same.
Try to find out what your interests and hobbies are and pursue them. Maybe you like singing or music or drawing or painting or writing or photography, whatever. Find out what interests you and follow that. Don't worry about bringing bad name, etc. We cant please everybody.
Everyone of us is unique and blessed with some unique talent. Dig into yourself and ask questions like what are my interests, what are my liking, what is my life purpose, etc. and you will find answers. Take help of your family members, or friends or YourDost counsellors. Don't judge yourself. Don't be harsh to yourself. Just love yourself unconditionally. Be a best friend to yourself.
You are very young and there is lot of future for you. You can do so many things in life and be an example for others. I wish i were in your place so that i could do so many things with life. Unfortunately i am old now and can't take your place. Anyway, take good care.
All the best dear.