AF ? implantation?

ashley
so I had a very light, to what I think, AF on the 16th and 17rh this month. the 18th I had no bleeding.. but a tiny penny size spot the night. Same on the 19th had super little spotting that was pinkish red light. 20th nothing and today very light pink spotting again. 
usually when I have a light 2 day period I don't spot or have any bleeding the days after. 
meow I'm curious, could it be implantation bleeding ?! 
I want to test in a few days just to be sure. but any opinions ?