Late period orrrr???

So I use to be on the pill but I got off probs a year ago. And ever since I've had my period for 4 days with pretty painful cramps and not a really heavy flow, and I've always been right on the day every 29 days. Well yesterday all day I didn't get it I had cravings and weird cramps but no flow. So I woke up this morning and took a test and it was negative but I know that those can be defective so... what now? I'll keep you guys updated if I get it. I'm just crazy weirded out lol