Hey missi,

Here's my (un)expert opinion

So the luteal phase is the part of your cycle between ovulation and Day 1 of your cycle, when AF arrives. As far as I'm aware, it is supposed to be standard, as you say below, each month.

So that's how we know when we have ovulated (more or less) - by counting back 14 days from AF. And that's why its so hard to predict when you will O, because the time between AF (Day 1) and O is changeable for some women, each cycle can be different.

Most women have a luteal phase that lasts 10-16 days - averaging at 14 days. It should generally be the same each cycle.

I'd say its more likely to be your OPKs that are confusing the issue. I haven't used them but I know from other girls on here they can be notoriously unreliable!

Hope this has helped!