Weird Traffic Stats Lately Even Though Consistent at #1??

So I'm seeing really weird traffic stats lately and I'm wondering if anyone else is experiencing this. I've had a kw consistently ranked #1 in the UK for the past week or so. I check it every day with different UK proxies, as well as an international rank checker add on in firefox . The weird part is that one day I'll get a surge of 200+ visitors from the UK , and the next- like 10 visitors. I know this isn't a bot or anything because I get a lot of leads on the day it surges with one of my aff networks, and very little on the day it has only 10 visitors. My rank has remained consistent throughout this timeframe.....it's not dancing around or anything. What the heck is going on here? I've never seen anything like this before. Even with paid traffic. There is nothing wrong with my hosting account or anything, it's up. Oh yeah....I have the newest version of Piwik installed, and IT says my visitors from the UK are clicking the #1 result to get to my site, too. Help??