What Causes Nausea And Tiredness With Left Ovary Pain?

i have been having feelings of nausea and tiredness and excessive hunger for some weeks now. i thought i was about 4 weeks pregnant but i had what seemed like a period few days ago but the feeling has not subsided and i feel as though i could be pregnant. i have a 2 year old so i know the symptoms of pregnancy.i did a pg test before the bleed ing and it was negative. i am also having what feels like some pain in my left ovary. my breasts are quite sore and they would not normally be so by the end of my normal period cycle.