Was it implantation?

Niamh

So my period was supposed to come last Friday, I had one bit of pink blood discharge last Thursday on a tissue and think it was implantation as I haven't had anything after it or since. I have a few symptoms too and have had extra yellowy discharge. If it was implantation, how soon will it show on a test? I have tested but it was negative but sure the test line was trying to come through. TIA :)