Could i still get a positive?

Stefanie
Ttc for about 2 years now. Ive had irregular periods all last year but finally since January ive had regular normal periods! Well af was due 3rd week of may and never came. I took a test it was negative. Ive been feeling nauseous in the morning for the past couple of days went to the doctor negative test again and i have a slight fever but im not sick! Im so sad but has anyone been in thia boat and got a positive just later?