Implantation bleeding

La

I’m either getting my period, or experiencing implantation bleeding. The spotting is a dark brown colour, which I believe I’ve experienced at the beginning of a period before. However, I’ve been feeling weak and nauseous the past few days. Not sure what’s happening, anyone have any insight or words of hope? Not positive when I ovulated, but according to glow I last baby danced towards the end of my fertile window. Thank you for any replies xoxox