Implantation bleeding???

I have PCOS and my cycle is hard to track. Yesterday I had spotting (brown-reddish) when I thought my period might start or about a week before (again not sure of my cycle). I’ve never had anything like this happen. I’ve also been having back/hip pain on my left side. Could this have been Implantation or something else? Also how soon could I get a positive pregnancy test result?