Where has my good sleeper gone

[PCHead]

Hi, my 21 month old daughter has been an amazing sleeper since about 8 months (I did CC to train her up) but in the last few weeks she has suddenly decided she won't go on in her cot. I can settle her at bed time by getting her to sleep in my arms and then transferring her, but if she wakes in the night she refuses to lie down in it and proceeds to have a tantrum and will not settle until she is in my bed with me. I am trying to function on about 4 hours sleep and I work full time so can't catch up. Any advice welcome!

Is it worth just letting her get in with you so you can all go back to sleep, or is she likely to wriggle and keep you awake all night anyway? I don't think I would have the energy to deal with tantrums in the middle of the night!

Is she tired enough or does she need to drop a nap?

Thanks for your messages. She is only napping for about an hour a day so not excessive. If she's in with us, as lovely as it is, it means I don't really sleep for fear of her falling out the bed and I am concerned of the habit it is forming. She has been better the last couple of nights so hoping it was just teething...time will tell!