How soon after conception can i take a pregnancy test?

I just got married and had an early misscarriage in february. After the misscarriage, my period is 35 days cycles instead of 30 days as usual .Due to irregular cycles I plan to use ovulation kit on the 05/21 and it came out positive. I had sex on the 05/17, 05/19, 05/21 and 05/22. I used pregnancy test on may 30th, may 31st, and june 3rd and it all came out negative. Am i testing too early? Or i am not pregnant. My husband and i really expect to having a baby. Please help! Thanks.