I have got a 7 yr old daughter like yours and I came to the conclusion she is like she is because I split up from her father 4 yrs ago now and she doesn't see him, sometimes she worries that she will loose me too. I just reasure her and spend as much time with her as possible as I have 4 other children.
I think your daughter will get better as she gets older.
I couldn't help but think she sounded insecure when I read your email and then reading what Ang said about her daughter worrying she will lose her confirmed it. Your daughter following you around, needing to know everything, etc. just sounds like her way of staying in control of the situation. Whether her dad is in her life again or not, he definitely had to bring out a lot of insecurity in her. She's probably scared and doesn't know how to articulate it or may not even realize it herself! Kids have ways of getting under your skin and if you look at them too closely, it will just make them worse. Keep reminding yourself of the great things about her. Watch her silly expressions when she sings and notice how cute they are! It sounds like you were frustrated and needed to get it out, just stay on that track!