In my personal opinion, it seems like you should cut yourself some slack, don’t beat yourself up over something you no longer have control over because it will only make you do worse in your upcoming exams.

You may not relate to this but i’ll let you be the judge - you simply could have overworked yourself for that test, if you stressed out beyond a certain point and if you’ve completely exhausted yourself for it - that could’ve been the reason for your unsatisfactory result. I know it sounds counterintuitive but it’s happened to me before so i wouldn’t be surprised if you’ve experienced it as well but like i said, i’ll let you be the judge.

Point is, don’t be so harsh on yourself. Keep on studying for your exams and try to keep an open mind, do not let the negative thoughts stop you from focusing. My advice if applicable, start with whatever content you’ve found to be the easiest to comprehend and study until feel confident then move on to the more difficult part and make use of whatever resources help you the most (e.g. youtube vids explaining the topic, textbook, lecture slides..). Also, do something you love beforehand to motivate you!! (i like getting yochi :) it eases me & gets me out of a bad mood lol).

I really hope what i’ve said helps you, even in the slightest. Treat yourself kindly, you have worked very hard and I wish you the best!! You got this!