Conservatives like Daniel Hannan and Conservative Home are suggesting that UKIP "lost" seats for the Conservatives. And enough seats that they don't get a majority.
Mathematically, if you add UKIP votes and Conservative votes then this is probably true. However, that's very simplistic. UKIP voters aren't necessarily inclined to vote Conservative. Personally, if there wasn't a UKIP candidate I'd probably have been more inclined to vote Lib Dem. There's very little in it between the 3 main parties but at least things like electoral reform are more likely to happen.
Seriously, there's huge gaps in policy between UKIP and the Conservatives. Yes, the Conservatives might be slightly smaller government than the Conservatives, but not by much. Over Europe, they're basically pro-EU whatever meally-mouthed things they say.
And seriously? You're blaming UKIP? In 2005 you had a leader who was likened to Nosferatu fighting against a charismatic politician in the middle of a boom, and you got 32.3% share of the vote. Fighting a terrible PM in one of the worst recessions ever, and you got 36.1% of the vote. Maybe you should look in the mirror and ask why you couldn't get people to vote for you.