I had unprotected sex on the first day of my last menses,and I got and used plan b the next day which was less than 72hours,then two weeks after that I had sex twice but with a condom,but am about 4days late and I am a nervous wreck right now,I had constipation last week,been having headaches n some kind of pre menstraul pains and sorebreast too,I did the hpt twice,3days apart and it came out negative,what do you all think?