Could it be implantation bleeding?

So I’m late on my period. Like very late (20 days or so). I’m not sure if I skipped my period altogether but I had some dark pink blood the one morning (just enough to see on toilet paper one wipe — TMI). I have worn a tampon a time or two since then but nothing but a small amount of brown blood has been on it. I haven’t seen it on toilet paper since that first day.

This is definitely not normal for me. Could it be implantation bleeding? Should I test?