Hi Diety! I relate so well to what you are saying. I use to struggle so much in math and science, and use to be very scared of both subjects. Today however I am a tutor for chem/bio and psychological statistics along with aspiring to be a physician. I even took my MCAT (medical college admission exam) without a calculator and yes I needed to solve problems that were math related! The point is to never give up and to keep working hard. When I was in high school and I wanted to pursue the path of medicine I devoted my time to studying because I knew that math and science was important to this field. I know sometimes it may seem difficult to reach out to teachers and receive their help but if you show dedication you are definitely going to catch their attention. At the end of high school I took AP Bio and I was still scared about the sciences especially an advanced course that covered college work, but I kept studying and kept reaching out to my teacher and asking questions even when I felt uncomfortable or afraid. It's perfectly normal. At the end though I did a great presentation for a topic on the angiotensin system which my teacher loved and she even wrote in my yearbook how dedicated I was.
The passion about science comes with time, sometimes you need to research and you can find a field of science that really makes you interested. For example, you can love anatomy and be okay with chemistry. The point is to appreciate each science as they all relate but don't worry about having a passion for each of them. I love chemistry/biology, the truth is though I struggled with physics, but I definitely understand it's work in the medical field therefore I appreciate the subject as well. I don't know how old you are but if you're still in high school keep working hard and try to reach out to your teachers! In high school there was not tutoring programs so most of my help came from my teachers and my best friend who studied with me in AP Bio. If you can find a good group of friends or even one that will study with you and you can support each other that will help greatly. Try to volunteer as well, especially with animals in nearby shelters if you can! Get to know the practical side of your passion, because once that happens the academic side will seem easier. Once you get to college there will be more help, like tutoring services free of charge for your classes, in addition you are matched with your adviser who helps you out in picking courses and keeping you on your path. I don't know this for vet school so you may want to double check, but for medical school you can be any major and take prerequisites to gain admissions to a medical college, instead of the traditional hard sciences. For example I was a psychology major because I love it and there is so much more to be explored but I took many prereqs for medical school and even gained a minor in chemistry.
That being said don't give up, every field has it's own obstacles and if you really are passionate and definitely decide this is meant for you just keep working hard, staying focused and reaching out for help! Best of luck!