I haven't had a chance to talk to you which makes me kind of bummed out.
この場合、次のような言い方が自然な感じで良いと思います。
ーI haven't had a chance to talk to you which makes me kind of bummed out.
「あなたに話しかけるチャンスがなくて、落ち込んでいる」
ーI didn't have the courage to talk to you at the party last Saturday, and I'm quite down about it.
「先週の土曜日のパーティーであなたに話しかける勇気がなくて、落ち込んでる」
ご参考まで!