Here's what works for me (65-year-old female, BP I): Ambien 10 mg, Benadryl 50 mg, and melatonin 10 mg (plus lamictal). Oh my goodness. Eight hours a night, restful sleep, feel like a million dollars. I even bought a smart watch and can see my sleep patterns: 4 hours deep sleep, 4 hours light sleep. Technicolor dreams. Very refreshed. Absolutely can't wait to go to bed at night.

I stumbled on this combination about 4 months ago. But YMMV of course.

Have you ever tried Trazodone? Made me manic, but lots of people like it, I think. Sometimes stopping things for a week or so and then re-starting works; Ambien is this way for me.