Normally blood and or a urine test usually can identify pregnancy very soon after the implantation, usually as early as 6-8 days after the egg has been fertilized.
If the test comes back negative and you think you are pregnant, wait a few days and take another test. Or call your doctor and have the blood or urine test taken to find out for sure. Another resource to bookmark is for stretch mark prevention.
It is quite common for women to use morning urine to take their pregnancy test. It has been advised taking your test at this time, as this urine usually contains a higher a concentrated amount of LH. It is suggested to use urine from later on that morning or sometime in the mid afternoon.