Hi Rachel, yes just get to sleep in any way you find you can. Your sleep will be disturbed for awhile, but sleep is important for healing, both physically and mentally -but in a few months (sorry but that is the truth *), you will be as good as new.
* When drs say months, or whatever I think we all secretly say to ourselves "Yeah that is for other women, but I am different - and watch me mate.. I will show you!!", however, as a survivor of 11 years i can tell you they are right HAHA!! SO be patient, take things extremely easy, but do the gentle arm exercises (do you have the BCNA Pilates DVD.. that is designed with gentle exercise/movements that can be done from day one- it is not gung-ho pilates.) You want to keep your shoulder moving, but gently!
I work for a plastic and reconstructive surgeon so see many over a long period of time and those that do best are the ones who are not silly to themselves.. not too easy for us girls though eh? We want to return to the old us, but have to accept a new normal- each day is a gift.
Use pillows to support you at night in whatever shape you can adjust to but if in doubt do ring your surgeon's rooms- you are covered for after- care dont forget and they want the very best outcome for you!
XX Mandy