Upvote:3
You failed your landing interview and got a Temporary Admission (TA) instead of Leave to Enter. You were served a removal notice, and your passport held; this is now part of your UK Immigration record.
While you are have been allowed visa-free entry into the UK in the past, you would be better served to apply for a visa, rather than risk appearing at the border and being refused entry (immediate removal). With a husband and daughter in the UK, and previous lengthy stays (per your chronicle of events), it is very likely you are suspected of trying to live in the UK rather than pursuing the appropriate route of a Family visa, as you noted.
Now, before travelling to the UK, you should apply for entry clearance, making sure that you include the reference number of the notice you were given in December. As you intend to emigrate, you would want to avoid any more strikes against you on your immigration record.