You do sound quite low at the moment. Make sure you are eating sensibly and get to bed at a reasonable time.
It is not long until exams are finished so please try to keep going with your revision. Some of your competitors may give up now & they may regret it later.
Don't overthink what the results will be. Live in the moment and do what you can now.
Later in the summer there will be different paths to consider. Lots of people change track - this is a normal thing to do so don't worry about what others will think.
This is an uncertain time but you can control the work you are doing now. If there are specific topics that make you lose sleep, find some past paper questions & review the mark schemes carefully.