When is too soon to take a test?

We have been trying to get pregnant since we miscarried back in Oct 15'. I am due tomorrow to get AF so fingers crossed that we took this time around. I want to take a test but I don't want to be disappointed. So my questions are is it too early, and if I take one and it's negative does that just mean that my hormone levels aren't high enough? I pretty much know the answer but it's nice to hear advise from others dealing with ttc.