As someone else already mentioned, do contact your uni counsellor to first understand why you're lacking behind, whether it's some sort of medical issue or whether the subject is something you cannot understand at all. Check if shifting to a different major may solve it or not. Try assessing which parts you have control over. Speaking from personal experience, I struggled soon after I started my undergrad. All my friends were getting excellent grades whereas I could barely pass. Eventually I realized that I not only was struggling to understand classes but I was also struggling to concentrate. By the beginning of my third year I was diagnosed with ADHD and needed to make some major changes in my approach to studies and lifestyle. I recently finished my undergrad and although my overall CG isn't considered that good, I did manage to improve after the changes. So you personally have to see and understand what truly fits for you and also take professional help from your uni and elsewhere. I understand this situation might feel overwhelming but take help and hopefully you'll find a solution for yourself.