My phone started acting up yesterday. When it's not being charged, the battery goes down to 3 bars when I haven't used it at all. When I do use it, the battery drains to 1 bar really fast. And when I use the internet, my service randomly disconnects and doesn't work. When this happens, I see the word "SIM?" blinking in the top right corner where the service bars usually are. Anybody know why this is happening?