I had sex september 29 but my period doesn't start until october 19. when do i take a pregnancy test? do i have to wait until my period?

U can do one: 3-4 days before your period is supposed to start.

After missed period: Conception occurs within day or so of the sex. It takes about 3 weeks for the embryo to make enough HCG for a positive pregnancy test. Blood test may be done a day after a missed period. Home pregnancy tests should be done 4-5 days after the missed period. If the result is negative repeat the test in 4-5 days. Use first morning urine and follow instructions for the test carefully.