When should I test?!

My period was due to come on Christmas Day and I still haven't had any signs of it. I've been feeling kinda icky but nothing like I did when I was pregnant with my first I know pregnancy a can each be different but I'm having a hard to deciding if I should test or wait. I just don't want to see a negative, it would be so upsetting. So when should I test? Thanks ahead of time yall!?