I wasn't feeling well this morning, so I couldn't go to school.
I couldn't make it to school this morning because I was so sick.
ーI wasn't feeling well this morning, so I couldn't go to school.
「今朝調子が悪かったので、学校に行けなかった」
I wasn't feeling well で「私は調子が悪かった」
ーI couldn't make it to school this morning because I was so sick.
「気分が悪くて今朝学校に行けなかった」
to make it to ... で「…になんとか出席する・都合をつける」
I was so sick. で「私はとても気分が悪かった・病気だった」
ご参考まで！
カナダ 
