hace una semana
La semana.
esta semana
La semana.
Cada semana.
Lets say a month is 4 weeks. Anywhere from 6 months and a week ago to 7 months and a week ago.
fin de semana
Translation: Una semana
Hace mucho tiempo.
It is most likely a glitch that is causing a photo you posted three weeks ago says that it was posted only one week ago.
The translation is "siete meses pasado."
last week I swam = Nadé en la semana pasada
"Diez veces a la semana."