The reason that your total is lower than it was before is due to unsuccessful donations being made to your page.
When donations are made and all of the details on the surface look correct, we assume that the payment will go through and we pull the donation through to your page. Sometimes when we send this information to the bank a donation isn't successful and we try to take it again over a 24 hours period - during this time the donation stays on your page.
If the donation is still unsuccessful at the end of the 24 hour period then we remove the entry from the fundraising page, which is when you'll see the total change again.
This is a new process that we have introduced to ensure that we give payments as much time as possible to go through so that we can raise more for the cause you have chosen.