I would first question whether you ned to try a different driving instructor? If you are feeling overly stressed or out of your depth it's probably because you are. Your instructor should have noticed this a long time ago approaching test and ensured the level at which you train and drive matches your confidence and ability level. Often it is caused by rushing through lessons regardless of the need to repeat them. n aspiration is to feel totally confident on any road anywhere. yes it can be done. If you go back to taking extra time to get the basics right, of being able to judge, speed, distance and the width of your car then learning is easy.
Ask around to find out which instructors are good locally with student anxiety. When you are confident that you can drive in any situation and settled you will be in a much better head space to do your driving test where you just drive some random person around safely for 40 mins. The Web site 'Safer Driving for Life' also has some good free advice for learners and for students getting ready to take their test.