Don’t panic, you haven’t gotten the results yet! You might have done better than you thought… it might just be the exams are harder this year and the grade boundaries might be lower, you don’t know yet, so don’t beat yourself up.
Worst case scenario you don’t get the grades to get into your dream uni, there are still a lot of options, such a taking a gap year or going through clearing to get into another uni. You could also apply for a foundation course in your dream uni
Don’t lose hope yet!! Wishing you the best of luck!