Cycle's usually 26-28 days long.my lmp was august 4th. my tracker says i ovulated august 18 but hubby and i had sex only on august 21. i got a few positive pregnancy tests. im confused how i concieved if i was 2 days past my fertile window?due date?

Too early to know: 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.