Please Help!

Kristen

So my fertile week was two weeks ago and my husband and I were very active during that time. My period came on Sunday and is usually about 5-7 days long. But this time it was only 3 days. It was a lot lighter than usual, could it be implantation? I don’t want to get my hopes up or anything and I just took a test and it was negative. Am I just being stupid? Help me please!