Is 13 days long enough to find out????

If you were ovulating on the 6th then it would be long enough, but since you had sex 18 days before your next period is due you probably ovulated sometime between the 8th and the 14th. Early pregnancy tests can detect from 10 days after ovulation, providing that implantation has occured early enough.
Good luck

I just finished having my peroid like 3 days before the June 6th. So, is there a chance I could be. If not when should we be doing it to get preg??? I was told to from start of period to count out 13 days and have sex all 13 days. This is what a doctor told me in Albany New York. Please help me.

It is not very likely that you would get pregnant from sex 3 days after your period ended. You are most fertile between 10-16 days before your next period is due. This is when you ovulate. Many women trying to get pregnant have sex every day or every second day from the end of the period until when the next one it due. Using this method, you are sure to catch the fertile time. Check out fertilityfriend.com for more conception help