mom not being fair

My LO is 2 months old. My husband is in another country, I'm doing the paperwork to go. Currently I'm living with my mom but she never helps. It's very tiring taking care of him 24 hours. I don't have time to do anything. I don't even have time to enjoy a cup of coffee or relax for a few minutes. He cries every night and she never comes to ask if we are okay or offers help. My sister has two older kids (10 and 5), she goes on vacation a lot, once a month, and leaves the kids with my mom and she never complains. She babysits three times a week but with me she wouldn't even hold my son for ten mins till I shower.
Just venting...