It's a really difficult degree, hence why most of the time it leads to a graduate-entry Medicine and Dentistry.
Don't be put off though; if you work really hard and pick the right modules (ones you find genuinely interesting) you'll be fine. I passed and didn't really do that great, just scraped a 2:1, but that's because I didn't take it very seriously and it wasn't something I wanted to do as a career. However 95% of my classmates got really high 2:1s and firsts. 75% of them went on to be graduate-entry doctors and dentists.