I had the exact same thing happen yesterday, too! Only it was one of my older machines. The upper thread kept getting caught and was nesting under the feed dogs, instead of going all the way around. Took me 2 hours to figure it out. I took everything off, unscrewed everything, dusted everything, talked sweetly to it, felt like an idiot, tweezed some lint out of it, patted it, put it all back together, and THEN it sewed like a dream. I swear to god these machines have personalities. I think this one was just lonely because I'd been using a different machine. Holly - I wouldn't say the money was wasted just because you're having a problem right now. It's very likely there's some small thing you're missing simply because the machine is new to you - ask me how I know.
If your hubby is the helpful type, ask him to watch and see if he can figure out what the problem is. Sometimes it's helpful to have a second pair of eyes & hands.