I am 4 days late...negative HPT's what is going on?

I have alot of syptoms but it could be PMS....my have been hard for like 2 weeks NO JOKE!! and they sting a little....I have cramps (but they dont really feel like normal period cramps those usually ache this is like a painful twinging) and am very wet *tmi* Has me running for the bathroom Tampon in hand like every hour and NOTHING....I am soooo emotional I cry over commercial LOL have been having headaches almost daily for 2 weeks not bad ones just very slight....my bowels are all messed up *tmi* I have to pee like every damn 20 min also my cervix is VERY high and soft and closed I think....I know this isnt a sure tale way to know just thought Id mention it......is it possible to be prego and still get BFN tests?