Help!! any1 get dizzy from lack of exercise, fatigue? :(

Hello
For 2 years now i have had a stomach disorder and it makes me feel pretty rough alot of the time, so i dont work or do a whole lot these days.
But i also get light headed and feel tired and a bit dizzy at times!
Does this sound like it could be the cause of my lack of exercise and bad diet i have!! although i have stomach issues i still eat really bad and healthy foods all the time!!

Hope someone can help :)