My child doesn't want to go to sleep!

We are having huge problems with DD at bedtime. DD (almost 2yo) has been a model sleeper for over 18 months now. She has a solid bed time routine and would talk and sing until she fell asleep each night. Recently she has taken to screaming, and I mean SCREAMING when we put her down. To the point where is starts coughing and has even thrown up... That sounds really bad but it only takes 5 mins for her to get to that stage....

So now we get her back up when she starts getting too worked up. We would never just leave her to scream we do verbal reassurance (I know not everyone agrees with this but it has worked really well for us in the past)

We end up taking her for a drive to get her to sleep. Even the mention of bed or going to sleep (on us, in our bed etc) incites more screaming.

She has had a string of ear infections this winter resulting in grommets. She got the grommets 2 weeks ago and got the all clear from the doctor today.

The only thing DH and I can think of is that she has the memory of sore ears when lying down and doesn't want that again BUT she has gone to sleep perfectly for my folks, sleeps well at daycare and is hit and miss with day naps at home. She has recently gone from 2 to 1 day sleep.

Any advice would be great... We are at our wits end with the screaming...