Another Period Question....Sorry But I'm Late

Jettscy

So I'm on Ortho Tri Cyclen lo, and I'm two days late ( my periods are usually early but their never late.)  I think today I am at 16 dpo and I took a 20 mlu pregnancy test (not first morning urine) and it said negative.  I haven't been stressing or doing anything out of the ordinary.  I have been trying to have patience, but I have been trying to skip my daily workouts and taking my weight loss pills.  I feel like I have wasted a day if I don't workout.  When is a good day to test and should I buy a test with a high mlu level?  Does it sound like my period is just late or something?