Your last LMP ended on March 6th (the last day you took your contraceptive
Prior to that date and after, you had unprotected sex. Your HPT on 31st
?March was negative. What was your Sexual relationship after the 31st. Assuming that you had sex / had no sex, you didn't get your periods and do any pregnancy
But the symptoms look like you may be pregnant (especially your Breast presentation).
Better do a Lab (Blood) pregnancy test, get the result and act according to your wish - terminating or continuing - consulting a gynecologist.