Pregnancy test

Ms. Brooks
Christmas Day I took a pregnancy test in the evening. It had the line for positive for maybe 5 seconds and then it disappeared. I thought I was wanting to be pregnant too bad so I "google'd" it and supposedly, if there is not enough HCG to make the test completely positive it will do this. So I have promised myself not to test until my HCG levels would be higher. It's killing me not to test yet cuz I want a few kids and pushing 30 years old, I need to start soon. Has anyone heard or experienced this before? Please comment