Could this be borderline?

I'm a 15 year old Italian girl. During the last few years i've been seeing a number of psychologists because of my self-destructing tendencies and overall behaviour. I have been self-harming for two years and suicide happens to be one of the most recurrent thoughts for me.
At the same time I behave perfectly normal around people, if not a little over the top. There are times in which I love myself and times in which I find myself disgusting, I hate people or love them, I change mood constantly, bursting out and screaming at friends or family. I laugh or giggle inapropriately at random times. Once I saw a woman die in hospital and had to keep myslelf from laughing. Then I fall into depression and try to hurt myself in all ways I can (cutting, banging, burning, scratching, smoking, snorting pills).
I know there must be something wrong with my brain. I am constantly paranoid about little things, and my moods change radically in no time.

I've read both about Bipolar and Borderline Personality disorders. The main difference is the length of the depressive or manic moods, right? And the fact that Borderline might diminish with time (or actually be cured), is that true?

Could I have borderline? My psychologist doesn't seem inclined to diagnosing me anytime soon, should I try meeting a psychiatrist?

[ILADVOCATE]

We can only give our opinions. Only a psychiatrist can provide a diagnosis. However as for bipolar it causes a wide amount of mood variances and more. Its complex. Google "Depression Central" (for all mood disorders) for information. Behavioral that is self destructive and having trouble relating to people and setting emotional boundaries is part of bpd which is more complex and addition to medication requires talk therapy and cognitive behavioral therapy. When a person has the wrong affect (mood) for something that happens (such as laughing at someone's death) that can be a psychotic disorder. The good news is everything described is treatable. For bpd the antipsychotic Abilify or the mood stabilizer Lamictal are most often used. A psychologist conducts talk therapy and generally does not provide medication. Ask for a referral to a psychiatrist and see how they could help you and what the diagnosis and treatment is.