bitterly

The Lioness came up, and bitterly lamented the death of her whelp.

Unwilling to lose his filberts, and yet unable to withdraw his hand, he burst into tears and bitterly lamented his disappointment.

Sometimes she would cry bitterly for hours, with Toto sitting at her feet and looking into her face, whining dismally to show how sorry he was for his little mistress.

All his emotion then burst forth; he cast himself on the ground, weeping bitterly, and asking himself what crime he had committed that he was thus punished.