No period, negative pregnancy test?

Hey! I took a pregnancy test 2 days after my period was supposed to start and it was negative. I am now 5 days late with no symptoms of pms or signs of starting. I’ve had slight nausea, but only after I eat something I don’t agree with. What’s the latest you guys have gotten a positive result?

* I have been exclusively nursing my daughter for 9 months now. My cycle started back at 4months and has been regular and on time since. I’m not very educated in how breastfeeding can change a cycle, but my cycle had been regular up to this point.*