Pregnant? Not Pregnant?

My first pregnancy was a weird case, I took five urine test and five blood test before any doctors could tell me that I was pregnant. They was finally able to tell me when I was almost five months pregnant with my baby girl. In 2014 I had my second child and they was able to tell me in two months that I was pregnant with him. So now it's 2016 and I have missed my period for three, almost four months now and I took three test and all said negative like my first pregnany and still having symptoms. Me and my husband is convinced that we expecting baby number three and it's going to be a girl. Just like our first pregnancy. Have anyone else have a weird baby factory system? lol or is it just me?