Implantation bleeding, or after period clean out?

Breyanna

So... I was on heavy antibiotic about 2 weeks ago for bronchitis. After I had possibly the lightest period ever. I’m on the implant and it had just started getting regular but I’ve still been bleeding a normal amount. Me and my guy have sex regularly. I woke up this moving to brown liquidy discharge. I took 3 pregnancy test and all negative.

Is it too early for pregnancy to show up?

Or am I over thinking?