How to bring a weekly total into a monthly total

Hi Everyone, I have been kind of stuck on what formula to use to perform this function. I've attached an example so you all can see.

Basically what I need to do is track the number of referrals for a specific team member. I would need to have the total in cell B8 (Week Total) move into the month total. We need to keep track of their total referrals for the month.

Is there anyway to keep a running total as they change add their numbers?