I have been lovingly growing my carrots in my garden, but I have just discovered that they might not be carrots at all! The plants look like carrots, but the flowers are small purple flowers - and there don't seem to be any carrots in the ground!

Please could someone tell me what this plant is?

Is it possible that the seed company has sent me weed seeds - these plants have only come up where I have sowed carrots?

I've got photos, but don't seem to be able to post them here...

HELP!??! Thanks.