I am feeling constantly nauseous, extremely tired and have a bloated stomach and a heavy feeling in my stomach

For the past few months I have felt constantly tired although I have a long day I am always in bed for 9pm and up again at 6.30pm. I work all day on a computer screen and the telephone and the waves of nauseau have become more frequent. I have an ache around my eyes and ache in my lower back and just feel completley exhuasted. My husband had a vasectomy 5 years ago so i know i am not pregnant!