Have i disappointed god

Im 17 years old and lust has taken full control over me I frequently masturbate and ALWAYS have lustful thoughts.I have been struggling like this for over a year now and when i suddenly became religious i have a feeling I let god down because i promised him I won't ever feel or do anything like this again but I will always repeat this sin. I feel like this emotion is bringing me down so much and god is just disappointed at me.