What's going on?!

So I rarely post anything but here's a little story. I got nexplanon in December and have had a total of six periods since getting it. This time once my period went off I started sipping vinegar to delay the next one (sometimes they come 7 days apart or 12 days apart). I was suppose to get my period last Thursday and didn't so I assumed the vinegar worked. Sunday after the gym I took a shower and had brown discharge but not as dark as usual. That lasted until Tuesday and it was VERY scant. Today nothing at all, regular day no discharge, blood etc. I have had unprotected sex with my SO. Could it just be the BC or is that what you would call implantation bleeding. Help!