FALSE NEGATIVES?

Anyone get false negatives like the first couple days of late period and still end up pregnant? 
​I am about 5 days late. Extremely rare for me because even after miscarriage I was right back on track with a perfect 28 day cycle. First day is usually very heavy and painful!!!
Had intercourse 10/8/14 (kinda messy) withdrawal. Bad headaches, extreme fatigue and back ache. This morning took a test BFN. Wiped and had a little pinkish brown streak. Put a tampon in for one hour, took it out & only a few very light pink spots with sticky clear discharge on it. Also have been having quite a bit of lotiony & clear discharge. Crying or mad at just about anything, appetite EMBARRASSINGLY increased lol and gassy. What do you think?? Wait it out or get to the doctor for a blood test?