Talk to Gynecologist on Pregnancy

hey I don't want pregnancy due to some problems and my husband just fingered me about 35..40 days ago...I may have doubt that may be a drop of precum is on his finger so can I get pregnent by that ??? as I mentioned I don't want pregnancy now so I consulted to gynacologist and she gave me birth control pills named as " omatril" after using 25 tablets I stop I stop taking pills I had periods for 5 flow of that flow is less thany own natural when my periods ended I had again bleed after 5 tell me why did that happen ???? I also go through beta HCG blood test who's value is less than suggest me that is there's need for retest ?? or can I get pregnant by that ???