To test again, or no?

I have been TTC for four months now. Was on BC for 8 years. Since getting off BC in December, my periods have been on time every month and I have ovulated correctly. 
This month, though, I was expecting my period on Sunday (according to the app prediction) and have yet to have a visit from AF - it's now Friday. I have never been late - ever. Took a line pregnancy on Tuesday - negative. Took one again today - negative. I haven't had any signs of my period. I spotted ONCE yesterday but it was very light pink. Should I take a digital test tomorrow or just chalk it up as my period being way off track?