SOS internet connection problems

Hello,

i'm Karen. i'm 16 and a freshmen student. i usually borrow my older sister's laptop so i can access my accounts. just a few minutes ago, i was browsing through my Facebook, then, i went to the bathroom and when i came back, i tried to access another website and puff, nothing happened.all i can see was the internet connection not available, well in fact the little icon is registering an internet access to my sister's laptop. i tried to follow the Google help center's suggestion but it didn't work. i'm so nervous right now. i know when my sister would wake up later this morning, she'll find out about this problem and curse things on me again. i don't what know to do. please help me.