I was worried you might have been involved in an accident.
I was a bit concerned something bad might have happened to you.
この場合、次のような言い方ができますよ。
ーI was worried you might have been involved in an accident.
「事故に巻き込まれたのではないかと心配でした」
to be involved in an accident で「事故に巻き込まれる」
ーI was a bit concerned something bad might have happened to you.
「あなたに何か悪いことが起こったのかもとちょっと心配でした」
something bad might have happened to you で「あなたに何か悪いことが起こったのかもしれない」
ご参考まで！
カナダ 
