Hi,
What about a home pregnancy test, did you take one of those? I'd say no if you've been having periods, did you have a period in the beginning with your other 3 children? You'd know best though :) If you're body is producing the same symptoms as when you were pregnant with your other 3, anything's possible. If you are trying to get pregnant, good luck to you on the blood test and let us know how it goes :)