2 missed periods

Hi, i have now missed two periods. I'm 2 days late for this one. However, 3 pregnancy tests have come back negative. Is this possible? I have no symptoms of my period. No cramps or anything. But i do have very sore nipples. Is it possible to be pregnant and it NOT show on home tests? I am going to go the doctors this week as last time he was very uninterested. I am only 18 and i have mentioned to my mum that i have had no period she's been very supportive! I'm awfully confused. Any help would be massively appreciate! TIA ❣️