How far gone before preg test positive?

[TreeHuggerMum1]

I have two boys already and both were negative preg tests at 3,4 and 5 weeks.
Am now wondering if I am pg again but again testing BFN!
Am I a freak??
Anyone else out there that doesn't show straight away??
Be good to know...

I didnt get a postive urine test until 3 weeks after I was due my period. I knew I was pregnant because I never suffer from heartburn! However after three weeks of negative tests I gave up on the idea. The last one I did was a complete fluke purely because it was the last test left, and shock shock- BFP!!- I'd had an operation two days before this test where I had about 3 sets of bloods taken from me, and they didn't even tell me!!! So it either still wasn't showing even in my blood, or those paticular doctors were just incapable!! Pretty shocking as I had an anaesthetic and was pumped full of painkillers, although my GP seems to think I should be fine. Every test I have done since has come up positive hooray!

not just me then. i have a 7 mth old son and really think i'm pregnant again. no idea how late i am but last period was in feb so i am late. got a bfn off a test today but it was not a first sample. i suppose i could be wrong.