It is very frequent for green hand to lose data during the process of transferring data from iPhone to computer, once you realize you have deleted some data by accident, you should stop using your iPhone at once, since if it continues to work, some new data will overwrite your lost data.
This is my precious experience of
recover iPhone lost photos, from this point, you can get to know how often I have lost my iPhone data
Hope it can help you!
Read more:
http://www.recovery-ipad.com