I am 12 days late and I feel nauseous

I'm 12 days late on my period and I feel nauseous everyday. I don't feel pregnant. But I sleep a little more and u feel sick before or after I eat. Doesn't matter the tine of day I always feel sick. I took a pregnancy test 3 days ago and came back negative. I will be taking another one on Friday (it's 3:25am thursday right now) I have been google'ing like crazy and alot of women have this problem. I am 17. My birthday is in 10days so I plan to go to the doctor when I turn 18. I see no reason of telling my mother. Right now I feel dizzy (I am Laying down on my back) I have always had problems of feeling dizzy but it never happened this much same as the nausea. I want this to GO AWAY.! My boyfriend is stuck on the fact that the pregnancy test said negative but I'm worried about the fact it said negative but I feel nauseous and dizzy and sleepy. I already have big breast so there doesn't seem to been any growth. My boyfriend asked me today are home pregnancy test accurate. I said yes by 97%. Is it possible I'm in the other 3% of having a false-negative test.? Heeeellllpppp Meeeee Plllleeeaaaassseee.! I do not want a baby right now and I use protection but he did go in w/o a condom twice but that was only for 7 or 8 stroke/pumps or whatever he wasn't in long both times. What could be the problem to this nausea,dizziness,fatigue,false pregnancy test. I also feel some uncomfort in my lower stomach right now. No pain just some uncomfort