@LeeanneD11 all sounds like typical normal pregnancy symptoms for this stage, the backache, the tiredness, the larger breasts, all good signs in my opinion. I had a MMC in December and my symptoms 100% left, i mean i could have stayed up partying all night, boobs where just normal, i had zero zero zero, you have a few symptoms and that is very typical, especially at 12 weeks.
Try to think positively and obviously the scan will tell the tale, but there is more chance of you going in and having a good scan than a bad, wishing you the very best and please let us know how you are getting on x