Implantation spotting? Or what?

So I had my period on Dec13 and went on til Dec17. Was off it for a few days and you know did the baby dance. Then on Dec27 I had a quicky before work. Started cramping like for a few hours, like around 8pm I started spotting, (Pardon the details) it look like egg whites with some reddish brownish blood. The crazy odd thing is it only lasted like three maybe four hours top.

Has anybody had this? Or explain if it could be implantation bleeding? If yes, then those this mean I could be pregnant?