I'm glad you're enjoying it!
- The Potion of Invisibility lasts for 3 hours, so you only use that right before you enter a dangerous part of the swamp.
- The Broom of Flying lasts for the entire next night (all 8 hours)
- The Helpful Helper lasts for the rest of the game, which will be at most 2 nights, since you cannot summon it until the break between the first and second nights.
Was the Helper the one causing confusion?