Help!

Hey all! So I took a blood HCG test Friday and they were lower than two (so obviously negative) I was due for my period on Monday. Then Saturday night my discharge was slightly pink. Then Sunday nothing. Monday hardly anything (tiny spotting when I wiped once, dark like old blood) then today same thing. No full on period just a tiny bit of spotting. Not even enough to drip on my pants just tiny dark spots when I wipe and thats not even every time I wipe (only sometimes). I have never been late. My period always starts right on time full blown. I don’t know if I should take another test or not? Should I just wait to see if my period comes fully? I am approximately 16dpo. What do you think it is? Period coming just slowly or implantation? Please help.