15 dpo and Negative tests?

Hello. Currently 15 dpo. Ovulated December 30th. I took my first test 13 dpo dollar store brand and all negative. Took a few more 14, negative. Then invested in first response to only get another negative result.... is it safe to say I’m not pregnant and wait until af is going to come? I’m still holding on hope that I am? Any success stories of testing after 15 dpo and getting a positive? What do you think? Thanks . As for symtooms I felt Nauseus and fatigued had mild cramping but it’s hard to know , thanks !!!!
Answers

Kangaroo

A test will normally be positive 15dpo if you are indeed pregnant. But, unless you were having IUI (or IVF and you've tracked back from transfer), you can't be 100% certain you ovulated then, so it's worth trying again in a few days.

Tri-Harder

The main question is how you determined ovulation and what your luteal phase normally is.