I highly doubt your tank was cycled. Did you seed it with material from another established tank? Cycling process usually takes about 6-8 weeks to complete. I would invest in a API Freshwater Master Liquid Test Kit, you can get them on Amazon cheaper than the stores, if you don't already have one.
If I were you, I would take everything out of the tank, gravel, decorations, heater, filter and rinse it all in warm tap water. Just get rid of any bacteria you might have had and start fresh. Test you tap water, does it have any ammonia in it to begin with? Set it all up again and fill with conditioned water, you do have conditioner, right? Turn the filter on and add the fish, if you're doing a fish in cycle, but I don't recommend that to someone without the experience.
All three of those articles are awesome. I highly suggest you read them, and I mean really read them. Also, PM Hallyx, he's awesome and can give you great information. He held my hand through the entire cycling process of my 5.5 gallon. He really knows what he's talking about.
Again, I would see if you can get another tank to keep your fish in while this is going on. You can really hurt your fish if you don't do it properly. Ammonia, nitrite and nitrate are all harmful to fish, some more than others, but if left untreated then your fish could get really sick or die. You have to be diligent on your 50% weekly water changes, no excuses. Again, make sure you have your own liquid test kit.
Hope that helps, happy holidays.