Looking for some help and experience

Has anyone ever tested before their missed period and gotten a negative, but then tested after your missed period and been positive? We have been trying for a couple months and I just started tracking everything with this app this month, I tested this morning and got a negative (sadly) but I am not supposed to start my period until tomorrow, according to glow. Just wondering if I could be but it's too early to tell? I ovulated (and had sex) 15 days ago, so is it really too early to tell? I am having all the symptoms, but they are also pre period symptoms. I am just confused and trying to be hopeful, I would appreciate any feedback from anyone!!