hi michelle, i had the same thing happen to me i am now 25 weeks pregnant with my third child but i knew even before my period woz late that i was pregnant i cjust had the same feelings that i had with my other two. i did a test wen i woz 3 days late which woz negative, then other 3 days later which woz also nnegative. so thought i had maybe got it wrong and my period would just start late. when it didnt i did another test and by then i woz actually 16 days late and it woz positive, i cudnt understand why this happened, give it another week and do another one, if it is still negative just ask at your doctors if you can get them to send one of for you.
good luck hun, let me know how you get on.
dawn 2 girls 9 and 6 and 25 week baby boy bump xxxxx