Help please

So I’ve been bleeding for 3 days now and on the first day the blood was different like it was more watery and lighter in color and as he say progressed I bled a bit of red a brown but not enough to fill a tampon in 4 hrs like usual. On the second day the blood was a bit darker and more red but the flow was very light and I filled a tampon in 6 hrs. On the third day there was barely any blood on my tampon and it was brown blood. I’m wondering if it’s implantation bleeding or af. I haven’t had any cramps and no clots so far in my blood