Please help me out

My period date is Monday (26dec ) - but am bleeding or Spotting ( I don’t know what to say )

Very dark brown blood was there in like 3-5 drops every few hours for 22dec - 23 - 24 - 25dec.

After that No Drop No Blood No Proper Period

I always have heavy Cramp in periods but when I was Bleeding/spotting the dark brown thing , there was no Cramp

Took a Pregnancy Test On 26 ( yesterday ) but it was a clear Negative!

What should i do ? Was that Old Blood or implant Spotting ?