That looks like chickweed (Stellaria media) to me and I doubt you planted it. It pops up as a "weed" in most places that are suitable for it. However, it makes a fantastic edible fresh or cooked, so don't pull it up! If you want to compare the traits and see how to use it, check this link ...
https://www.wildedible.com/chickweed.
Also, I could be wrong, but it looks like you may have some tiny carrot seedlings coming up at the base too.