What does my "friend" mean by this?

Her and my other "friend" ignore me when it's us three and they both take me for granted and one of them texed me last night at 3:30 am saying HEY! Wake up. I ignored her, the she just sent me a text saying you suck ;) I can't tell if she's being serious or joking. What's your opinion? and I don't want to text her back she just uses me.