Whats happening in my body?

I wake up on my own at 6 or 7:00am. as i go to the bathrom and go to brush my teeth.My body keeps on Trying ,and trying to puck but nothing comes out. so my body wont give up until i get up on my feet...During the day i feel nausea, craving for salty foods, my body wouldnt accept fruits and orange juice doesnt taste the same.their are times that i feel nausea during the day and it leaves.I could never finish a full coarse meal,my stomach is expanding,after i eat my stomach gets a little bigger than before. My stomach is looking like a 1 -2 mo. pregnant women.I feel exhausted all the time...I have very strong Lower back pains.I only could sleep on my side...i have had sex a week after my period.I had went 2 days with out my body trying to puck and the next morning it hit me hard .And i had to missed periods. my nose is sensitive sometimes.I get hungry all the time more than ever and i get chills very quickly.could this be a baby or a problem? please tell me... im a little worried over here...