Just sleep on your back if that is what is most comfortable at that point in time. I'm surprised the recent research advising not to got so much publicity when you actually look into it.
The research showed that lying on your back does cause a 'stress' reaction in the baby during the period you are on your back. The conclusions that have been drawn from this is that there MAY be a link to stillbirth, but it isn't entirely clear why those particular conclusions have been reached as every single pregnancy/baby involved in the study was born alive and healthy.
A previous study a few years ago focused on asking recently bereaved mothers who had a stillborn baby the sleeping position they had favoured in the run up to giving birth. Again, the results drawn from this study are not entirely conclusive that sleeping your back is a defining factor in still birth, its just one of many possible factors and possibilities.
I've said this previously on other threads that it makes no sense to me that the female human body would have such a design flaw that something as straightforward as a comfortable sleeping position could be THAT harmful.
I do believe however that the human body is clever enough that if something isn't quite right it makes us uncomfortable and makes us seek a different position to become more comfortable. So actually in the later weeks of pregnancy lying on your back can become very uncomfortable for some women, so they don't do it any more anyway.
The answer however, in most cases to getting comfortable is to double the amount/ size of pillows you have available now and make a nest for yourself, find a comfortable position and sleep in it for as long as you can 