Very sorry to hear that, they don't see you because they dont look. You could buy a dayglo reflective jacket or cover yourself with fairy lights but if they dont look they are still not going to see you.
Only thing you can do is buy quality leathers, boots, gloves and helmet (doesn't have to be expensive to be good), stay alert at all times and imagine every car is about to suddenly swerve and hit you.
The driving test is too easy.