後：あと or ご？

In my recent diary, I wrote 一週間後, and I noticed Google’s Speech to Text was pronouncing it as ご instead of what I was thinking: あと

After searching around, here’s a quick summary.

あと

Used alone or in casual phrases

• 後で電話します。I’ll call you in a bit.
• 後は任せるよ。I’ll leave the rest to you.
• 仕事の後で after work

ご

Used in compound words or formal expressions

• 一週間後 after a week
• 放課（ほうか）後 after school

So if I want to use あと, it would be 一週間の後, now あと is considered used alone instead of part of the compound word.