Could the tests just be defective? I only get faint lines?

First of all, most cheaper brands of HPTs are actually made by the manufacturers of the more expensive ones. You need to look at the sensitivity to see how early it will detect, and how much, the pregancy hormone HCG. That being said, there is not right or wrong when it comes to the darkness of the line. A general rule of thumb is that if there is a line there, then there's a line. No ifs, ands, or buts about it. That line will ONLY appear if there is pregnancy hormone detected in your urine. I would suggest scheduling an appointment with your physician to get a blood count, as they are more definitive. Good luck!