Yes, it is possible. but it can take several weeks before a positive also.
i took a first response home preg test to get my positive... we conceived the baby on dec.15 and i got my positive 12 days later on dec.27.
good luck to you!
it all depends on what type of test you get and how much your hcg levels have rose. a doctor can do a blood test now to detect if you have hcg levels above 5, which means you are pregnant but home test usually can not detect them til you are at least at 25. Once the fetilized egg attaches, which can take up to 10 days after sex, you then start producing hcg and it should double at least every 3 days, so that can take sometime 3-4 weeks afetr conception to test positive on a home test.
i hope this helped:)