Your post does not scream bpd. Self Harm / suicidal gestures are fairly common symptoms / traits of many disorders. The isolation would be more common with depression. Also, mood swings, the inability to concentrate, and self hatred could be depression related. In regards to online friendships/relationships it's not uncommon for those to be short lived. I think you have something going on, but not bpd or any other personality disorder for that matter.

Of course this is only my opinion.