I would contact your gp if it’s been 7 days. Since having my daughter 5.5 months ago I’ve been regular every month the same date pretty much 29/30day cycle x
Similar happened to me and the GP wouldn’t see me until I missed 3 periods in a row 😩 I wasn’t pregnant and got my period the next month, I just completely skipped a month with no changes at all in my life and my daughter was like 7 already.
I was the same, periods were all regular until about 8/9 months pp, then I missed 2 periods and went to GP after negative tests. Everything came back fine, hormones and not pregnant. She said it can just take your body a while to adjust after having a baby x
Well the most straightforward answer to your question, when to contact gp is when you're concerned, sounds like now. When I got pregnant with my son I had 4 false negative tests over 2 weeks. Potentially reassuring thought is babies change all your hormones and that can change how regular your periods are unfortunately. You may just be experiencing new cycle adjustments now that you're postpartum