|confusion regarding pregancy|

Generally I have irreular cycle due which Ireally cant predict my ovulation.. Last monthI have y periods on 3 july and after that I and my husaband is quite regualr.. But on 17 july and aroun 22 july we have 3 time a day due to his off ... All protection were taken but till tomorrow there is no signs of period ... Then we decided to do pregnancy test today in the morning.. But at midnight during sex I got spoting which I thought may be my periods, because inthe morning also there is a spot.. But still we have done the test two times and its negative... I could see a little bit of spotting but till now but not a major flow.. What should I do.? Should it still be pregnancy ? Shoul I go for scanning as the two tests were clearly negative... Please help !