Nagging bitch
A nagging bitch is someone who texts you like it's her full-time job and she's getting a raise every time she sends you a message.
'You said you'd come over, but now you're telling me you're going to sleep instead.'
'I know you're busy, but I'm still going to send you 50 messages about it.'
'You didn't even say you'd come, so I'm sending you 100 messages about it.'