When to test ... irregular periods and used a condom but late

[Laurenemma13]

Hi All,
This may me seem like a bit of an odd one.
I have a hospital appointment on Monday as I've been bleeding after sex each time. I've also had very irregular periods where my longest cycle is 18 days in the past 9 months.
It's now been 30 days since my last period which is unheard of for me.
My husband and I did have sex when I would have been ovulating, 14 to 15 days into the cycle however we used a condom.
I did have some spotting on Friday (not abnormal at all) though nothing since then and have had cramps since then but no sign of period yet?
I know there is a small % chance with condoms but with being so irregular I have no clue when to take a pregnancy test?
Anyone any ideas. My thoughts were to wait until day 35 and if nothing by then, test?

If we are pregnant we'd be happy as we had planned to start trying next month.
Thanks in advance x

If you can afford to do a few tests, why not do one straight away?

I guess I'm a bit worried about getting a 'false' negative!

So just a quick update. Day 32, no period. I've taken a test and its come back negative.
Does anyone have any ideas when I should retest if still no period?
I have no idea
Given that we used protection, I've had no regularity with my periods and I've had a negative test I dont think I could be?