Light period or implantation bleeding?

Hi all. I’m hoping someone can give some insight about what could be causing the unusually light bleeding I am having at the moment. My periods are normally quite regular with a bright red colour, medium to heavy flow. This time my period was 3 days late and the colour dark brown. The flow is very light and comes and goes. It’s been going on for 3 days now and I’m not sure what to make of it. I stopped taking contraception since September last year and we have been trying to fall pregnant since. I had two irregular periods for the first two months of trying but my periods have normalized since. Has anyone ever had a similar experience, and could it be that I’m experiencing implantation bleeding? I have done some reading online but would prefer hearing from actual women.