Still negative!

So, for the last week or so I've been having extremely sore boobs/nipples, appetite has gone waaaay up, light cramping (but not like AF), been nauseous....and I'm still getting negatives on the dye tests! My period is supposed to start today but so far haven't had any kind of spotting or anything. I'm currently 15 dpo so I feel like I should at least be getting faint positives if I am pregnant. 😟 should I just give up?