Anyone help?

So I stopped the pill on 27th July and had my withdrawal bleed on the 29th for about 5-6 days. According the glow I would of ovulated between 10th-12th and I actually got a positive opk on 11th. Now it’s saying my period was due yesterday and I was getting cramps and pains like I was going to start but nothing so now I’m one day late. I know my periods can be messed up from coming off the pill but if I wasn’t going back to normal then why did I get a positive opk? With my last son, I got pregnant the second month of coming off the pill so I feel like I regulate quite quickly and my first son was 2 months of coming off the implant