Implantation bleeding

Hi ladies! I'm currently TTC. So according to Glo I ovulated on the 3rd of July I had BD on the 28th and the 29th of June. I'm 5 days before AF is due. Yesterday I had brown spotting/mucus when I wiped and today I had this and it had stretchy brown discharge I also have a bit of cramping on the left side of my abdomen and my left arm/shoulder/neck is a bit sore... could this be implantation bleeding or just pre period blood??