For some reason the payment threshold shows $0 but it's my understanding that it is still $50. If so, you'll need to earn a bit more to make the threshold for the next pay period.
The top number represents lifetime earnings and the bottom number is for the current balance in the account.
When I passed $50, it reset to 0, but I didn't actually get my money. I have "earned" $85.15, but I have not recieved anything at all. Notice the part where it says, "Last Paid: Not Yet." $52 was removed from my CC account without actually being put into my PayPal account.