Can implantation bleeding go from orange to brown?

I had some heavy spotting on Friday and it was orangey-red. Yesterday I hardly had any but again what I had was orangey, though at one point when I wiped I did see some bright red flecks, but mostly just orange. Now this morning I have some brown spotting. Could it be possible this is implantation? I have cramps, but so far they have been very mild and I've had some lower back pain (the back pain is not normal during AF for me). My period is technically three days away. Any thoughts?