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The reason I ran away without saying anything is that I didn't want to lose love.
Literal
Nothing saying-without ran-away [nominalizer-の] [topic-は] love [object-を] did-not-want-to-lose [because-から].
A confession in literary cleft form. 何も言わずに ('without saying anything') uses the classical/formal ~ずに paired with the negative universal 何も ('anything'), which in combination with a negative verb forms 'nothing.' 逃げ出す ('to flee, break away') is a compound verb 逃げる + 出す. ~のは~から is a nominalized 'because' clause frame: 'the reason [nominalized]のは is [reason]から.' This structure foregrounds the motive and delivers it as the sentence's main point. 愛を失いたくなかった ('I didn't want to lose love') uses ~たい in the past negative form.