I feel like a bad mom...

my so and I live with my parents I have a 14 month old and am 37+4 days pregnant. My niece (10yr old) was over and in my daughter's room across from mine playing I had the entrance to the kitchen and living room blocked off so my daughter could not go toward the doors. My mom was home. and I fell asleep for maybe 20 minutes. between that time my dad came home. then my sister came over to pick up her daughter. (the moment I fell asleep someone took down the babygates I had put up and did not put them back up. )My sister came in the front door and only shut the screen ( the screen doesn't shut unless you lock it) she didn't lock it. My niece and everyone went into the kitchen leaving my daughter alone in the room knowing I had fallen asleep. she walked out the front screen shut it behind her and sat on the porch. My sister came in saying omg where's (my daughter's name) ! I woke up and they saw her on the porch and brought her in. I cryd my eyes out because my baby could have been taken had someone came in the front gate. (my so is at work) I made sure before going to sleep to have her secure so I knew she couldn't get out. Am I a bad mom? Or was it even my fault? I feel like shit.