How soon can you conceive after a miscarriage at 6 weeks...?

I had a natural miscarriage at home last Thursday. By my ultrasound on Sat morning my uterus was completely empty. I was diagnosed with Hashimoto's thyroiditis by my endocrinologist yesterday - however my ob/gyn says there is absolutely nothing wrong with my thyroid! Of course I believe the doc who's specialty it is to diagnose the thyroid before I believe my Ob/Gyn... but why such a discrepancy? I had tests other than blood tests to confirm the Hashimoto's so I am not doubting I have it - plus I have the classic symptoms and before being on meds did not ovulate. ... My obgyn also said since I did not have a d&c that my lining is still in tact and we can wait just one cycle or begin trying now if we wanted - she sees no reason for me not to get pregnant right away again. I am still sad and depressed a little so whatever happens happens I am not jumping on the baby making train so soon, but wouldn't be sad if it happened... my question is... what would the odds of getting re-pregnant so soon? Is it common? I just would think it would take time if it took time before... that it wouldn't happen so fast. Does it? Can it?