Getting these kind of hallucinations can be a sign that your potential bipolar disorder is taking worse course and needs to be controlled with meds.
Antigone has right about possibility of experiencing mixed episodes (this kind of episodes also tend to occur more often when the bipolar is left untreated)
Bipolar disorder with its episodes is known to have seasonal pattern of appearance.
These hallucinations can be a side effect of using some antidepressants, too.
Visiting a psychiatrist will be a good idea!