Implantation or weird period ?

Hello! My Husband and I don’t use protection and this month my period was suppose to come on the 15th it has been the 15th since my miscarriage in April. Well this month it was two days late and when what I think was my period coming was on the 17th.

On the 17th I woke up spotting and it went to what a normal period on the first day would look like medium/heavy. Then the 18th and the 19th it was just very light spotting I could probably get away with 1 panty liner for both days ( I changed it of course but to give an idea how little I was bleeding.) I barely had ANY period symptoms.... just very mild cramping and low back pain. Blood was pinkish/redish. And occasionally when I wipe its like I have brown discharge only when I wipe.

What does this sound like?

When should I test? Since I already did yesterday and it was neg.