In the first place, if something is travelling backwards and forwards, it doesn't necessarily have to have begun, nor have to end, somewhere. Put something on a Mobius strip and it could keep travelling on it forever.
In the second place, according to Einstein's relativity theory, the Universe has four dimensions--three spatial dimensions (length, width, and depth) and the fourth dimension, which is time. Now, according to Kaluza-Klein theory, all of reality was once a perfect 10-dimensional Universe. Since, time then was embedded in spatial dimensions, it didn't flow in the same way we understand it now. This 10-dimensional Universe was unstable, however, and it "cracked" along the fourth dimension. The higher order dimensions--fifth through tenth--shrank, while the lower order dimensions--first through fourth--expanded, and our Universe emerged. Currently, the higher order dimensions, or "hyperspace" for short, are incredibly small relative to our Universe, so small that we don't notice them, though they're there. In time, hyperspace will start expanding, our Universe will contract, and the higher order Universe will reemerge.
In the third place, science does not form theories, nor laws out of nothing, but out of observation and logic. There are relatively few laws in science, and a lot of theories which most scientists admit haven't been proved yet. If you think scientists are stupid and religion the only truth, then you answer me a few questions:
1: If a flood killed everyone on Earth but Noah and his family, why is there no record of this event in the histories of any culture (Chinese, African, Indian, etc.)? If this really happened, then Asians, Africans, and so forth should have been wiped out, too. Do you think the vast profusion of people and races, including Native American, African, and Asian are all descended from Noah and his family?
2: If ten plagues really devastated Egypt, why is there no record of this event in Egyptian history?
3: If God is perfect and created Man in His image, it follows that Man's image is perfect. But our bodies, in terms of shape, are far from perfect. We are each born with an appendix, which does nothing for us. To see things better, we should have eyes on the sides of our heads, like lizards. We have necks that contain windpipes and throats, to take air to the lungs. But, to prevent choking, those two tunnels should be in different places.