I've been doing pretty good by using adwords to link directly to an affiliate page - which I know is risky Today I doubled my ppc budget to see if it would drive more sales and my clicks skyrocketed but I had no sales. My whole days budget was gone in 2hrs. Is it possible someone else promoting the same product saw my add and purposely kept clicking it to kill my budget for the day? Do people do that? WTF?
Google has systems in place to stop the second and subsequent clicks from the same person counting - so the attack would have to come from multiple IP addresses - this would be rare. The best clue is your CTR - if it is stable, then there's probably no sabotage. If it is up a lot, maybe click fraud. If it is down a lot, maybe impression fraud.
Changing your budget shouldn't make your advert more noticeable - it'll still appear in the same position. If you are running out of budget before the end of the day on a regular basis, you may want to cut your cost per click - that way, you'll get more clicks for the same money. I'd look at an hourly report of clicks over the last 7 days or so (by day). Does the pattern of clicks look different for yesterday? Also, do you have your delivery set to accelerated (in the campaign settings)? If not, Google may see that you've got more budget, and completely change the distribution of your adverts.