Beazlebub is spot on. The PPL exams are the lowest hurdles you'll face on the way to becoming a commercial pilot and if you can't find the enthusiasm this early on in the journey how do you think you'll fare later on? The road to becoming a commercial/airline pilot is long and arduous. To succeed you need more than just ability, you need determination, commitment and application.
I have met aspiring pilots who have ploughed tens of thousands of pounds into their flying training but, if truth be told, they were never going to pass while they still had a hole in their proverbial!
Not only have you struggled with the most basic exams you'll encounter but you have failed an aptitude test. Ask yourself how much you really want to become a pilot? Are you prepared to embrace the sacrifice and commitment that is required?
I hope I don't sound unnecessarily harsh but perhaps it's time for a reality check?