You were working too hard. I think you overdid things a little.
I think you pushed yourself a little too hard.
この場合、次のような言い方ができますよ。
ーYou were working too hard. I think you overdid things a little.
「働きすぎてから、ちょっと無理したんだね」
ーI think you pushed yourself a little too hard.
「ちょっと頑張りすぎたんだと思う」
to push oneself a little too hard で「すこし無理をしすぎる」
ご参考まで!