Do you still have those icons somewhere else?
It is possible to drag those icons off of the bottom bar, and even replace them with other icons once they are no longer on that bar. It is possible they are in a folder or on a second screen. It is not possible to delete the icons, however, so they
should still be on your phone, but if they are not you will have to restore your iPhone, which can be done from iTunes. To put them back on that bar if they are on your phone, touch the icons and do not move your finger. They(all app icons) should start shaking. They are then movable. To exit the "move icon" mode, just press the Home button once, and the icons will stop shaking.