Having trouble with my iPod touch?

My dad gave me an iTunes card for Easter and instead of hooking up to the computer and going through iTunes on it, I decided I would try to download straight from the iTunes on my iPod touch. So I did. I bought 19 or 20 songs. They all went into the area where they were supposed to be downloading to my iPod or whatever. After I used up all of my card I went to go check on how they were downloading. They hadn't started yet because I forgot to push the on. So I pressed the on to start it going. The little blue bar filled up slowly, like normal. But one thing I noticed was that the little "time left" countdown thing got to zero before the blue bar was filled up. It stopped when it got to zero anyways and went to the next song in line. The first song in line said "download error. Tap to retry." So it went through all of the songs I bought like that. Every single one. When the last one in line was done, I went back up to the top and tapped the first song to retry it. This time it went really fast through each song in the line. I still had "Download error. Tap to retry." I've done this like five times and I just don't get what's going on. What do I need to do to fix it? Thanks!