Hi,
Pls. check with your doc on that one. Overdosage depends on lots of different things, like gender, body size, empty stomach, in certain combinations with other meds, etc. VERY RISKY to guess!

I feel for your sleep troubles. I suffered with that for many years. Actually had to take chloral hydrate at one point.
Take care and I hope you can catch some Zzzzzz...
Take care,
Okie