How soon after miscarriage got pregnant

Hi everyone, I miscarried July 13th I was 6 weeks and 3 days. I was seeing a fertility dr. A week after the miscarriage my fertility dr did bloodwork to make sure my levels are where they should be along with an ultrasound to make sure nothing was left and all was good! She has told me I need two months to rest before I can conceive again. I’m going at the end of this month for bloodwork to see if I’m close to getting a period and if not she is starting me on provera to get the ball rolling. I asked my fertility dr why this could have happened and she explained to me a 15% chance as of chromosomes. So my question is do you need a shot for this and curious how soon everyone got pregnant after a miscarriage? Thanks ladies