Sickness and its effect on your cycle

Greetings! Newbie here.

I am TTC and have only started tracking my cycles for the last 6 months or so. My cycles are 27 days (and have been since I started tracking).

This month it's been 29 days and still no Aunt Flow!

I was a teeny bit excited thinking maybe I was up the duff but did a test and got the Big Fat Negative.

Before I go out and buy every pregnancy test known to man, does anyone have any experience of being unwell and it impacting on your cycle?

FYI - I've just had a grotty headcold that saw me in bed for 3 days and 7 days later I still have a sore throat and am a bit grumbly.

Thanks all! And great to be here :-)

Thanks Tarns.
Yeah, here's hoping! Will keep you posted :-D