My advice is this. Ask yourself - what are my strengths? Where do my talents lie? Find out what you are best at and go for it - concentrate on the relevant studies. Think about what you would like to do as a career, and make sure it is something you would be good at and would be comfortable working in. Try to achieve good grades in your chosen subjects. Decide whether you want to go to university, college, or go for a trade. Do not worry about leaving your old friends, it's time to move on. In time, you'll get to make new ones.