Possible po bang preggy??

Hi tanong ko lang may nangyari samin ng partner ko nung july 14 then after 1week niregla ako which is july 21 almost 2-3days lang regla ko nun then after patak patak nalang na brown almost 1week na ganun pero alternate naman ng day kunwari may patak this day kinabukasan wala. Then now supposedly dapat meron na akong regla nung 20 or 21 pero until now wala pa din.