Congrats on your pregnancy
very common, your the second person i have heard this happen to over the past few weeks…. think the spotting could be implant spotting.
Both my sisters where told their dates were wrong, they had as much as 4 weeks added to their dates, my sisters EDD was 19th of dec, hospital said 21th of Jan, my niece was born on the 16th of Dec and she wasnt early… some on other sister, both their kids had small heads and petite babies
Dont be stressing, you will get another scan down the line they may changed your dates again
Good luck xxx