Wow, where to start...okay, here goes...
Try, try again -- It's very possible that you just fucked up. That's not a problem. It happens to everyone. A lot. The important thing is that you take a minute or two to reflect on your failure and then put your best effort into not making the same mistakes on attempt number two. Of course, repeated failures are never a good sign, so keep reading.
Reevaluate your priorities -- Some things are just hard. Land wars in Asia, dating people of incompatible sexual orientations, and getting a Ph.D are all examples of things that probably don't merit a first attempt and most certainly don't smile upon second tries. In the immortal words of Mark Twain, "...there's no use being a damn fool about it." Maybe you should look into a new, more reasonable hobby.
Get a bigger hammer -- Maybe you just didn't apply enough metaphorical firepower. The fact of the matter is that candles and pocketknives don't solve every problem. Sometimes you have to use floodlights and chainsaws to get things accomplished. I wouldn't recommend bringing out the heavy artillery in round one, there's no worse feeling than sandblasting a soupcracker, but if reasonable methods didn't work the first time, maybe it's time to get unreasonable.
Try a different angle -- Maybe you're going about everything in completely the wrong way. If you're storming the proverbial castle gates, it's important to consider that the designers and builders of the castle possibly considered that type of assault, and likely spent a good deal of time and money making the gates painful to assault. Don't attack a problem at its strongest point. Look for weaknesses, especially integral weaknesses, such as sewage outlets or heating vents that lead directly to the reactor core.
Eat your damn lemons -- Maybe this was all just a bad idea. Maybe you are just a failure. Maybe now is not the best possible time to be crusading for water, sugar, ice, pitchers, cups, napkins, and a small stand on the side of the road. Sometimes, it's a good idea to accept defeat and enjoy what you have rather than grasping for more.