Hello, I can definitely say that many, many people are in the exact same position you're in. It's not easy to make honour roll, trust me! There's so many people I know that consider themselves lucky to achieve 70%. What is your current average? What do you want to study in College/University?
And who is putting so much stress on you to get on honour roll? Is it a goal you, yourself want to achieve? Is someone like a parent or family member forcing you to try hard enough in order to achieve an honour roll status? Is it your friends, peer pressure? Teachers? Well, whatever the case may be, you definitely have to look at the situtation in the best interest of yourself and nobody else. You can achieve anything you want to achieve. With the right amount of perseverance and dedication you can achieve any goals or dreams you wish! Don't let anybody ever tell you that you can't do something! I've had people in my life put me down and tell me I can't do things. It was the friends who were there for me and supported me who helped me get through these tough times and helped me to ignore these negative comments. Do you have any close friends you could go to about this - who can help you? Also, never be afraid to ask for help. If you are doing poorly in a subject, or even poorer than you expected to do, then maybe you should look into hiring a tutor to help you. Don't be afraid of what other people will say - it's your life and you can do what you want. Grade 12 is a very important year and it's amazing that you are taking it seriously - good for you. I don't even know you, but I can already tell that you will be successful and be successful wherever life takes you. The reason is because you are seeking help.
If you believe that you can get better grades than you're getting right now, then by all means - go for it! However, you also have to be careful that you don't over do it and "burn out" because that could have a really negative effect on you and could potentially do more harm than good for you. Just make sure to balance everything and you should be fine.
You're asking what you have to do to get serious about school again - the answer is very, very simple! Take courses that you like and that you are interested in! That will help lead you to a career that you will love! Don't choose a career for the money or the prestige! Trust me, you'll regret it! Your career is something you're going to have to do for the rest of your life. You're going to have to wake up every morning and go to work! Make sure it's something you love to do!! Like I said, whatever you do - don't do it for the money or prestige!
To leave off, I would just like to say - don't let anyone else discourage you of your hopes and dreams no matter how impossible they seem. "No matter how impossible they may seem, you have to fight for every dream. Who's to know, which one you let go, could have made you complete."
I wish you the best of luck!
Message me if you need anything else, I'm always glad to help.