Pregnant?

So i was supposed to have had my period by the 3rd of this month and i havent had it at all. Ive had some minor crapping on and off but nothing. Ive had a doctors pee stick test but that was negative and now this week ive benn feeling dizzy every day all day so i know its not vertigo. I also have a very thick mucussy discharge and yeaterday ot was heaps thick and very green. Ive been really hungry and sometimes nauseous after morning meals and very sick when i dont eat breakfeast which i usually dont. Anu chance i could be pregnant even though the doctor said no?