Implantation Orr..

I normally have a period for 5 days. I have been trying for a baby for a couple months now. I didn’t start my period and my dr prescribed me progesterone to induce it. Well like i said normally I have five days worth of bleeding and this time being the FIRST time I started last Sunday around 6am, I had cramping so I put a tampon in thinking I’d start. It was a very small part on the top of the tampon but it was red. I put another in thinking YES I started and checked again around 1pm. It was now same spot but brown still a little section. At 5pm nothing was on it. And it’s been done sense. My dr told me to take a pregnancy test thinking it was implantation bleeding but three tests came back negative.

Is it to early to test? How many days after implantation can you take a test?!