I feel like I have to be so careful about what I say and do whenever I have a business meal, so my stress just keeps building up.
この場合、次のような言い方ができます。
ーI feel like I have to be so careful about what I say and do whenever I have a business meal, so my stress just keeps building up.
「仕事の会食では言動に気を遣わなければいけないので、ストレスがただ溜まるばかりだ」
to be so careful about what I say and do で「言動にかなり気を遣う」
to have a business meal で「(仕事の)会食をする」
to build up「蓄積する・溜まる」
ご参考まで!