There are 350 sleeps (350 days) until October 5 (Tuesday, October 5, 2027).
There are 350 days until October 5 (Tuesday, October 5, 2027) — one sleep per night.
One sleep per night between now and the big day — tonight is the first sleep, and the morning after the last sleep is October 5. Sleeps are the same as days.
350 sleeps is 50 weeks.