Possibly Pregnant!

Hi ladies! Last year I had two back to back miscarriages. one at 13 weeks and the second at 8 weeks. It was incredibly devastating and I sunk into quite a depression. Fast forward 9 months later and I am 6 days late! My cycle has always been 28 days and even after my miscarriages my period picked up right where it left off. I have a happy and healthy 8 year old so we were quite shocked after these two miscarriages. My breasts are incredibly swollen and I'm always tired. Two things I rarely experience with just a period. There is no doubt in my mind, I am definitely pregnant. Unfortunately, the tests are not picking it up. All of them negative. If I had to guess, I am probably only 3 weeks along, if that. Has anyone else experienced this before? My doctor wants me to wait another week to come in for blood testing, but I am just dying to know!