Hi, I know I am late in reading and posting, but I got a BFP on thursday and this weekend was extremely dizzy and lightheaded.. spacey. I actually started feeling like this even before I knew I was pregnant! I wish you and your sister the best of luck!!! Congrats! :)
I got very lightheaded... I found out on the 30th of June that I was preggers and 2 weeks before went to the doc because I kept passing out. He said I had inner ear and put me on medication. I went to the doc two weeks later and I got a very faint positive. I know exactly what your sister is experiencing b/c I went through it. I just say that DON'T let her take any medications b/c I believe that's why I had a miscarriage on Monday.
i have heard that you can feel lightheaded and like your equalibrium is off in the very beginning.