Drinking Water

I have an issue that I've noticed happening to me. I wake up and I feel sick and dizzy, and have a headache. I sweat a lot and I've been having fainting spells every now and then. I don't think I'm dehydrated on the grand scheme of things because I drink lots of coke and other fizzy drinks, but I don't drink any water at all and I'm wondering if that could be the cause of this? Before I hardly drank anything but that led to urinary tract infections and hospitals so I started drinking a lot more but only fizzy drinks and never water. But I read online that you need to drink water but I don't like to because it tastes horrible and it comes out a tap and I worry about germs and bugs. I'm not really sure what to do about this. I can't drink it if I don't like it and if it may be contaminated.