Spotting

So I’m on the pill and not due to come off it for another week or so, however I’m experiencing light cramps which i get every so often so that could be normal however this time I have super pink discharge which I’ve never had before with the pill. I have had sex where he finished in me with no condom but I know that the pill isn’t always 100%. I know it’s very unlikely but could it be implantation bleeding or just normal spotting?