Seven Seas pre conception tablets

Jodie
Morning beautiful ladies,
I'm wondering if you could offer some advice. I've been using the seven seas pre pregenancy vitamins for my last cycle and am now late. 
Like 35 day cycle late. 
I feel nauseous in the morning but no actual sick, sensitive to smells, and no standard AF symptoms. 
HOWEVER, I took a test 4 days early- negative. Took another at day 32- negative.  Took my third, a digital one, yesterday on day 34....NEGATIVE!! 
And yet still no AF. I am usually regular to 29/31 days. I'm wondering, the only difference in what I've been doing is the pills. Could they have messed with the cycle this much? 
Obviously every day without AF appearing is like an optimistic fairy tapping me on the shoulder whispering 'maybe they're wrong!'  But what do you realistic women think? 
Any thoughts welcome. Xxx