Seeing your doctor is usually the best step, they can give you advice and give you a pregnancy test. You don't need to sit round worrying when it will take little time, it will also be accurate.

But then can they find that out so soon?

Let me tell you I have 2 kids that were each concieved within 2-3 days after my cycle ended.

Well, go to your doctor or wait. They say they can test for pregnancy with blood tests a week after conception. You'll have to wait awhile hunn.