Am I pregnant?

I have irregular periods so I have never tracked my periods therefor I have been taking pregnancy test like crazy they are all coming out negative but I have plenty of symptoms that If I'm not pregnant I feel like something is wrong with me but I'm not sure I have felt very tired and sleepy my body just wants to lay down,nauseous,when I smell something i want to throw up everything sounds gross just thinking about it, first conctepation,now diarrhea,this morning I started feeling dizzy and light headed , earlier when it was about the 1st week that we had,had unprotected sex I had felt cramps and sharp pain in my abdominal but every pregnancy test have came out negative.