I think your 62 and 99 not only cares about your B but also care about you. When you're not feeding, they want you to get as much rest as possible so that you won't feel too tired. And when your B cries, may be they want to relieve you so that you won't feel too frustrated.
When I first had my B, I also felt like a BF machine. It seems that is the only thing that I am capable of doing. I was so tired, and when my B cries, I felt so frustrated easily, and I was borderline Postpartum depression too. I was so glad that there are people to help me out, otherwise I think I may go crazy and develop a full postpartum depression!
So try to take it easy and think more positively. Your 62 and 99 just wants to help you out. If you still feel very uncomfortable about their behaviour, try to talk to your hubby and may be have him gently talk to his parents.