When do i test?

So as you can see on the calendar my last period was on Dec. 5 I still haven't started yet. I am wondering when I should re test? I took a test Jan. 6 and it was negative. But I've been so drained I don't know if its stress or what I haven't been working out I'm too tired too I don't have the energy to. I feel so exhausted I just want to sleep. When do u think I should re test ?