Is my friend intentionally trying to make me feel selfish and inferior?

Okay so i have this friend who is living with me for a while and everything has been fine but sometimes I feel like she is trying to make me feel like she is better than me. She doesn't have a lot of money which I don't mind but then I over heard her talking with my parents who suddenly think that I take everything for granted when in reality I don't. Then like the other day she asked me for help on how to upload a computer game, which I did but she needed a password. Then when I came back down she was like oh I figured it out you just needed emulator obvoiusly since I don't play games I don't know what that is and shes not stupid. Usually when she figures out things and I don't she does it in a way where it was like yea I figured it out and you couldn't. Even though she's not aggressive, her attitude is almost smug but she does it with this kind of blank stare. I only feel this way because she comes off that way with other people (gets jealous of their high grades etc). I only get mad when people boast about how well they did but I know she gets jealous. Another time we were talking and I told her how much studying I did and my method of studying which is talking things out and then she was like oh yea well I did all the chapter problems and talked so much my throat hurts. Then this morning our hot water tank pretty much stopped working and she couldn't get any hot water. I guess it was another thing I take for granted since she told my mom oh you see how much people take hot water for granted, since back at her apartment she doesn't have any hot water. Now today we took an exam together and she kept looking over at mine not to cheat but rather to see how much of it I had done. Am i just being paranoid, because then there are other times where she is really nice and i don't see it, but whenever it comes to school and our home lives it seems she has a different attitude.