Any thoughts? TTC while breastfeeding!

So I'm TTC my second and I never had implantation bleeding with my first. I'm just wondering if you have had implantation bleeding before how soon does it normally happen. My period isn't due for another 9 or so days. I'm not completely sure of when because I'm breastfeeding my 11 month old and only had my first period last month. My last day of my period was the 23rd of December so I don't think it is old blood from that and TMI but my CM is brownish and not pink or red so I don't think it's spotting like my period is about to start. But I have been cramping a little here and there. Could spotting cause brown CM? I have never spotted before I got my period before so I'm pretty clueless on the difference between spotting and implantation.