During day fast i masturbated but did not reach orgasm as i realized what i an doing is a sinful act

During day fast i masturbated but did not reach orgasm as i realized what i an doing is a sinful act and stopped and quickly went to shower. My question is my fast still valid? And how to seek forgiveness from god i am so angry at myself as i retained from this act for few months but came again bcs i was so stressed and overwhelmed. I am so sad and angry at my self and don’t know what to do