Why did boudicca poison herself?

Boudica killed herself because she could not bear to live in a nation under Roman rule after her Celtic rebellion had been crushed. The might of the Roman Army had utterly decimated her armed forces, and there was no longer any hope of overthrowing the oppression by Rome of the Celtic peoples, or even of entering into a negociated deal that would have allowed them more freedom and a degree of autonomy.

She and her two daughters died by drinking poison in either A.D.60 or 61, but the location of their burial sites is not known.