Normally short cycle... When to test??

I have a 24 day cycle and am due for my period today (still waiting). I'm wondering if I tested too early... I tested on Saturday wth an equate early response test (blue dye) and got a suuuuuper faint positive... Then tested the next 2 days with a dollar store test and got negatives... 
Any ideas what's going on? Do I need to wait longer after missed period is due for the hormones to build up (i tested positive with my son at 4 weeks)? Are the test sensitivities different? Possible evap line /false positive?