About somach problem ..please help!!!?

well ...its has been a week now sice i have this stomach discomfort and a little bit of a head ace ....I switched all my foods to organc foods last week and also i started drinking a tab filter water ( bought the filter and put on my faucet) I drank that water for 3 days and when i develope a nausia and discomfort in stomach , i quite and got back to my bottle water,,,but i continue eating organic foods stating from 7 days ago now ...but i am experiancing this terrable nausia and stomach discomfot and noise ..but no diherria,,when i get this nausia and discomfort my head hurts just a little bit and fell like i am felling dizzy,,,,but not relly mostely i feel like my eyes get tired like i want to go to bed ........my appetite is still good, normal bowel color and size..so what do u guys think I may have ,,,my sudden diet change? the tap water?? bugs?? or more ....