When you look back over the last year you will have invested so much time and effort to succeed, particularly where you are juggling children, family and study time. When you see all the carefree younger element breezing through? - believe me they are not all doing so well as the superficial exterior would seem. Many are happy just to socialise and have no other cares in their life.
Sometimes the reality of just how much you have sacrificed, the reminders of just how much time and serious hard work you have given - up are now starting to loom large. You are understandably having a minor 'confidence crisis'
So the best advice I have is 'talk' yourself through in positive terms and say you are going to see this through. That you can 'do this' - The prep work (as in previous posts) is really crucial, tutors, past papers, best revision notes, songs, colours, pictures etc. Do everything you can to set yourself up good and ready. Cover all revision bases at a generalised core level then crank up the revision into the specialised subject areas you gamble will be on the paper. Believe in the power of your mind. You have a wealth of knowledge sitting in your head. Read the exam questions really carefully (don't miss any questions on backs of papers) Ask what each question requires in its answer (and specific key words for the knowledge) Do your best and trust in karma for everything else. If it is meant to be it will be. It sounds very much like it is. In your head aim for a distinction pass and work and revise like you need that grade. Then even if you 'just pass' - at the end of the day that is all that matters. Anything above that is amazing. Have a fail safe in your head that if it really all does go wrong you can do a resit or a reconfigure. Nothing in life is so dire that it means life does not go forward with you in it. Sometimes some of the best and most life changing experiences happen after failure. It is how you get up again and climb back on that really matters.
You have so much to be proud of in life so far and I hope everything works out for you.