my period is 3 days late... and that's not normal for me!

So today makes the 3rd day that my period is late every thing I eat gives me heart burn / makes me sick. I took a pregnancy test this morning and it came back negative. Not sure I am to early for the test to tell or what is goin On has any one else experensed this and was pregnant? I have a feeling that I am but I really don't want to get my hopes up. We have been trying for the past 8 months and I really hope this is our month!