Any fertility experts? I just don't understand how I am pregnant!

[LumpySpaceCow]

Hello,
I'm going to probably seem really stupid here but be kind!
We have been using natural methods of contraception with natural cycles app. I have a regular 28 day cycle. We had sex on day 8 (which was a safe day according to app) and day 20 (which I thought was safe!!). Signs of ovulation in terms of discharge happened around day 15 but I noticed it was still the same around day 17.
According to the app I ovulated on day 21 (which seems so late for a 28 day cycle). However I do have two temperature drops and rises from days 16-22.
Hope you've managed to follow all that!
Well it seems I am pregnant (which is of course always a risk when using natural methods) but I'm just confused to how given the times when I had sex! Can you ovulate twice in a month?
Thanks if you've managed to follow this!

You can't ovulate twice in a both, but your body can gear up to ovulate, not do it and then ovulate a few days later. I guess that's what happened to you, hence the fertile cervical fluid earlier in the month. Your period would have come late, if you hadn't fallen pregnant.

It sounds like this is an ok, even if not totally ideal outcome for you - I hope that's the case.

Thank you. That does explain a lot!
It isn't ideal but we will be fine. Thanks again!