Zoloft is an antidepressant, and can be used in bipolar patient with depressive episode.

Does she takes this medicine in combination with other medicine like lithium?
Is she always depressive with sad, anxious, or empty mood, feeling hopeless, feeling guilt, worthless or helpless?
Are there days when she has feelings of increased energy, activity, and restlessness with excessively "high,” overly good, euphoric mood, too?

no she onli takes zoloft, but yeah she is always depressed, an yeh sometimes she does have the highs as well,
but recently she's gone off the zoloft, and is realli moody all the time, and its bad sometimes, like a whole new person,, what can i do?

If she has mild to moderate level of mania "highs" known as hypomania, and major depressive episodes, she probably has bipolar disorder 2.
But, if she has episodes of severe mood swings, from mania to depression, the diagnosis is bipolar disorder 1.
Usually, antidepressants used alone without antipsychotics or mood stabilizer, can trigger manic episode in bipolar patient.
Sometimes, symptoms of mania and depression can be experienced at the same time in what is called a mixed bipolar state.
Symptoms of a mixed state often include agitation, trouble sleeping, significant change in appetite, psychosis, and suicidal thinking.
A person may have a very sad, hopeless mood while at the same time feeling extremely energized.

Your help will be to force her to visit her psychiatrist to reconsider her therapy.