Yes, very common. I get dizzy all the time since I have been pregnant. Often times seeing "stars" or kinda getting black and I have to wait for it to pass, usually happens when I have gotten up quickly or standing for a long period of time. I work in a hospital, so I have taken my BP when this has happened and it is low! Need to keep up the fluids, since our bodies need more blood flow to send blood to the baby we need to drink even more than usual. But I am with you, it's harder than ever to get in all the recommended water because too much water makes me feel sick too.