Oh no!!!  I think that the way you felt was completely normal, isn't it???  My poor sis had her in laws (a strained relationship at the best of times) in her hospital room, taking photos (she had burst blood vessels all over face) and deciding to accompany them from the hospital to her house and inviting themselves to stay for nearly two weeks.  She was relieved that I was there when she felt like having a good cry, and her mother in law wanted to come in the room and take pictures!!!  I felt for her!!!  Surely anyone would know that that time should be for the family to just settle and re adjust.  Worse still my sister (too sweet), was expected to and DID cook for them and make them cups of tea.  My side of the family stayed away and just helped her through it on the phone!

I think that your sister is just too kind Loolarbelle. There are ways to set boundaries so that friends and in-laws won't be overstaying their welcome. We can say something like “I'm already very tired and feeling sleepy” or “I have an early appointment with the doctor tomorrow”. Most should already get the hint and leave so that you can rest.
 
My dad is even worse when we have visitors at home. If he's tired and doesn't feel like entertaining guests anymore, he'll just go upstairs and sleep.