Implantation Bleeding!?

I ovulate late and I was supposed to start 4 days ago. I tested this morning and got a negative test. But according to the days we had sex I would only be 3 weeks today, still too early to get a positive. I have had a little blood when wiping yesterday and today. It's very little, not enough to show on a panty liner and it's pink/bright reddish. I don't usually spot before I start. Does it seem like this could be implantation bleeding? What was your implantation bleeding like? How long after it did you get a positive test? I'm super anxious! TIA!