Implantation bleeding - slight tmi

Lydia • 19.. TTC for my first baby.
Can somebody please explain what this looks like? 
Last week 2 different days I had blood in my cervical mucus.
Yesterday I had brown discharge so put a tampon in thinking it was the beginning of my period (due this Saturday) but after I took the tampon out which was kind of full-ish, I've had nothing since!
Feeling exhausted too!
Thank you x