Opinions Please

Courtney
I have been feeling very nauseous, and dizzy the past week. Stopping the car to throw up and in the middle of Christmas shopping. I took a test 14 DPO a day before peroid due and it was a BFN. I was devistated! Now I'm 16 DPO a day late on my peroid and woke up ready to throw up again. I don't think I can handle another negative test after three years of TTC and getting all negative results. What do I do?? I have another test already but I'm so scared to take it. Anyone ever have a BFN than received a BFP two days later?