Last period 8th January still getting BFN!!

Sharna • I`m 24 and married with two beautiful boys ages 4 and 5 Expecting baby number 3 xxx
Hi ladies my last period was on the 8th of January I've missed February period and now March! I've took numerous test and Evan had one blood test also negative.. Doctor said maybe I have polycistic ovaries (I knew it wasn't that I've got two children already and never had problems getting  pregnant) well any way she tested for it and checked my hormone levels in the blood that came back normal so it's not that.. I've got another appointment Monday to speak to her about were were going to do from there would love to no if anyone else is in or been in a similar situation ..? X