Hey, first I want to say don't worry, you're not alone. This was me. From failure to failure. Having repeated not one, but two years of medical school. In my final year of med school, I had a resit. I had failed the exam by two marks, and if I failed this exam that was it. I'd be kicked out. I was full of shame because the disappointment I made my family feel. Afraid of what will become of me, and what my future held. It was frustrating because I felt that despite working hard, there was always still a mistake on my part that kept holding me back. Now I've finally graduated and can finally call myself a doctor, and I'm glad I went through the failures that I did. It made me grow as a person.
My first piece of advice is keep going. Keep pushing. It is so easy to give up right now. What I've learnt is that in med school one of the things they try to weed out is those who lack the determination to keep going. The fact that you still want to fight for it so hard is the best thing ever. Sometimes we work hard, and it is just not good enough. And that is just alright. In those situations you just need to learn from your mistakes and keep pushing. Push your own boundaries, try to be better than you were before and never stop.
One of my biggest mistakes was not trying to seek help when I needed it because I thought it wasn't a big deal and I should just be able to suck it up and study. That is the worst thing you could do. Contact the medical school. Let them know about your circumstances. Your mother is ill, and that is the sort of burden that can affect your mental health and performance. We are currently living in a plague, seek online therapy, talk about your frustrations. We underestimate how much our mental health can effect our performance. If you aren't in the best place mentally, you will not be able to perform your best no matter how hard you try.
That brings me to another point, which is stop beating yourself up. Give yourself a break. Everyone goes through life at their own pace. Try to give yourself a little breather, even if its just a few days, to relax and clear your mind. Try to self reflect. Try to meditate. Exercise. Enjoy your day. You just finished that exam, you're about to start studying for another one, take a few days vacation to relax. And the most important part, is that while you take your little vacation, remember that you deserve it. Regardless of your failure, you deserve the time off. Cut off the negative people from your life.
As one of the people above mentioned, fight your uni over this grade change. It really doesn't sound fair what so ever.
Finally, to learn from your mistakes you need to work smarter not harder. I know its something everyone says but its true. Contact an academic tutor, contact a professor, or even a fellow student. See where you're going wrong. Regardless of how hard you try, if you aren't going over what they want and expect from you in the exam, you're just wasting your time. You could memorize every book from cover to cover, and you could still fail the exam. Do past papers, see what the professors actually expect from you, and learn how they want you to answer the questions.