Bloated stomach...throughout the day, dizzy spells, nausea, headache, poor concentration

HI,

I am a 39 year old woman with two kids that has been steralised, living in the UK.  My systoms have been coming and going for the past month, my latest one is the stomach bloating.  Gradually throughout the day my stomach swells up and by early evening i can look anywhere up to 6 months pregnant.  I am not over weight, i dont smoke and am not pregnant.

Just sick of feeling like thiseh 

ANy help can be greatly recieved

Thanks guys