Supply is way down today!

kris
My supply the last few days has been around 32-35/day. Today I might hit 28...what gives? 
I admit I wasn't as 'on schedule' with my pumping as usually am this weekend. We had my sister and her kids out to visit. I still pumped 7 times but it wasn't at a consistent interval. Sometimes I'd go 5 hours in between pumps but would pump for longer to compensate. And then I'd pump again 2 hours later. Would that mess with my supply?? I figured since I pumped 7 times like always, I'd be ok. Am I wrong in my thinking there?
Or is it normal to have an off day every now and then? 
And of course this is the day when little boy has eaten more than he ever has before!! Luckily I had a small stash in the fridge cause  he's eaten more than I've produced today. 
I pumped every 2 hours today like clockwork in case it was my crazy schedule this weekend that caused this. I even did a power pump last night. I'm also taking fenugreek, blessed thistle, and choked down a teaspoon of Brewers yeast in my oatmeal this morning.
Any advice or insight?