3 weeks and 5 days is really early to be bleeding. If you are having heavy bleeding you should go to the ER to have your levels checked. And I assume that you haven't missed your period yet, you could be having a chemical pregnancy. Which is a early miscarriage before a missed period.
What Chemical Pregnancy Means:
The term chemical pregnancy means that the miscarriage happened at a point that a missed period and biochemical tests, such as an hCG blood test or a home pregnancy test (checking hCG in urine), were the only evidence that you were pregnant. The miscarriage happened before an ultrasound could have shown agestational sac.When the pregnancy develops to the point that ultrasound could confirm the existence of the pregnancy, the term becomes clinical pregnancy. Thus, a chemical pregnancy would be a miscarriage before the fifth week of gestation -- or within about week after your missed menstrual period.
Symptoms:
The primary symptom of chemical pregnancy would be if you begin to have vaginal bleedingshortly after having a positive pregnancy test. Blood tests reveal low hCG levels that are decreasing rather than increasing.
Causes:
Doctors believe that chemical pregnancies happen for the same reasons as most other miscarriages –- probably because ofchromosomal abnormalities in the developing baby. It is hard to know for sure what causes these early miscarriages, however, because it is nearly impossible to retrieve any samples for chromosomal testing.
I had heavy period like bleeding at six weeks (It was red, clotty and thick). And I freaked out because I have had a miscarriage had an ultrasound and bubs was fine and still is at 15 weeks+5days. (: If you are cramping that's no good, but if not I wouldn't worry yourself but would book a doctors appointment to monitor you HCG levels. Trust me, miscarriages hurt.
If it gets heavy like a period I would be concerned...are you having any cramping at all?