Paris Jackson -- She Hasn't Grieved Over Michael Jackson's Death

Paris Jackson is stable and doing OK ... but she's dealing with some pretty heavy issues, including the fact that she hasn't dealt with Michael Jackson's death -- this according to sources connected with the Jackson family.

Our sources say Paris -- who's currently receiving psychological help at UCLA Medical Center -- has indeed felt bullied, but NOT by schoolmates. We're told Paris has had an obsession with comments people leave about her on social media and websites -- and the negative comments "really get to her." Our sources say she currently does not have access to her phone or the Internet, so the problem is temporarily solved.

Paris, one source says, is a "rebel." We've learned Paris almost got expelled from school after punching a student who "talked smack about her father."

We're told Debbie Rowe has expressed deep concern about some of the friends Paris has been hanging with -- friends who she believes have been a bad influence.

And there's this ... we're told the shrinks who have been helping Paris believe she has not really gone through the grieving process over her dad's death. In other words, a lot of emotional upset has been building for nearly 4 years.

We're told when Paris gets out of UCLA ... she and Debbie Rowe are going away together for 6 to 8 weeks so she can get better. Our sources say Debbie feels very strongly it's important to get her the hell out of L.A. for the summer.