Wishing one hadn't

• Showing regret
• Contrite
• One called round, being sorry
• Feeling sorry for
• Showing contrition
• Feeling bad about head of government upon downfall
• Having regrets about
• One breaking step showing remorse
• Having second thoughts about toupee, staying at home

Wiktionary Word definitions in Wiktionary
vb. (present participle of rue English)