Hi Keisha, if Monday works for you, then stick with it.
I would say your start weight was 161lbs and that this week you have lost 2.5lbs (if you are now 158.5lbs)
I had to re-adjust my ticker when moving from one to the other because of the change of weigh in day.
When you weighed at 161lbs last Monday, was that lower than the week before on W8? If so, take the numbers that work for you!!!!
Rosie xx