My friend is so clingy?

[Emma]

So my best friend always wants to hang out. Every day or every other day, she will text my phone or Facebook messages asking to hang out. Whenever we hang out, she ALWAYS asks for a sleepover and becomes demanding when I make an excuse. She called my mom behind my back posing as me for the sleepover once! An example: today I woke up and logged onto Facebook and she messages me within a few minutes saying we should go to the mall. (Yesterday she asked me to go out, too) I say we are going bowling (which we are) and she said "you could take me with you or we could just hang out all day." What do I say to this?? I want to be honest, but she blew up last time I did that but I want her to know I generally do not do well at sleepovers. They just aren't my thing. I like going to sleep and waking on my own time every day. I JUST want to hang out. No sleepovers. Thanks for all the help I get Keep in mind I do like my bff. She's super crazy and funny, so I don't wanna stop being friends.
Btw, I'm a really shy quiet person. She's really outgoing, so I find it hard to talk and trust her because I've been betrayed before. I don't tell her my secrets. She tells me all of hers. Sometimes she can be embarrassing and demanding without knowing.