Quick question

My last fertile day according to glow was the 19th. On the 29th and 30th I had left sided mild pain on and off. I know it's probably just af which is due tomorrow but could it be implantation pain. Which is why nothing is showing properly on a hpt. I'm sure af will come as my previous pregnancies I've tested positive day before or 5 days before with one. They think that pregnancy was twins but it was a missed miscarriage.