I had the same thing! My last pregnancy was a miscarraige too so I would have freaked out if I hadn't have had the u/s lady tell me what it was (not that I understood that part) but assured me that all was fine and that it would probably just reabsorb but if I had a little bleeding then it was probably just that working it's way out. Mine has reabsorbed and I'm now 25 weeks and wouldn't have known anything about it except for the u/s. One thing my midwife did suggest was to keep the u/s handy in case of a bleed to take with you to hospital to give them more info about what might be going on.

I'm sure everything will be fine. GL with the rest of your pregnancy!