hi there, if as per your calculation you are four weeks pregnant then so be it. Wait for another week and get your urine preg test and your blood hcg
levels done. If they are positive then get ultrasound
repeated and it will give you the correct gestational age
. Tho' when they can't see the gestationl sac at 4-5 weeks then it could be a case of blighted ovum
and that is the reason you have started bleeding . Don't lose heart and you may concieve again. take care.