Implantation or period?

I’m still nursing but we started to TTC. My period has been slightly unpredictable. Could be the 14-17th of any month. I’m roughly due to start this Thursday. This morning I had cramps just on the right side. Went to the bathroom and noticed bright red blood (medium amount). I thought maybe my period was early. I put a tampon in and took some Tylenol for the back ache. Went to change my tampon a couple hours later and there was a little bit of brown on it (very small!). I then put a pad on instead of a tampon. There hasn’t been anything on the pad since. I wiped a couple times and it was mucous light pink this morning as well. I took a pregnancy test and it says negative. Maybe too early? Am I pregnant ?! Anyone else with similar experiences. I never had implantation bleeding with my first.