I am sorry to hear about your miscarriage.
Make sure you did not leave a tampon behind in your vagina. Don't laugh, it happens. So feel every bit of the vaginal walls with your finger, including right at the top around your cervix to make sure you are 'clean'
A bad smell is normally a sign of an infection. So it is best to see your doctor to have it diagnosed and treated. Did your doctor test you for a bacterial infection after the miscarriage?
Best of luck!