職場で、通常４人居るはずが昨日は自分ともう一人だけ「んーもう、昨日は二人しか居なくて大変だったよ！」=I had a hard time because there were only me and another person there yesterday, why didn't you come here? Sorry I promise no to do that again.で可？
A: I had a hard time because only me and another person were there yesterday. Why didn't you come?
B: Sorry! I promise not to do it again.
あなたがやってみた文は書いたままで大丈夫ですけど、人と話しているとき、以下の会話は良いと思います。
A: For goodnessake! It was really tough yesterday with just two people. Where the heck were you?
B: My bad, man. I won't do it again, I swear.
んーもう = for goodnessake (怒っているとき、あまり無礼じゃない表現です)
heck は怒っているときに子供も使える言葉です。
my bad = 悪い (僕のせいだと認めるという意味です。)
swear = promise (両方を使えます)
アメリカ合衆国 
