Re: pregnancy signs
In the first couple of weeks (when it was too early to test) I found myself to be REALLY thirsty all the time. I also had a cramping feeling for at least a week or ten days before I could test (about a week after ovulation). I think that may have been from implantation. My breasts were also tender. As NYCGori said, many of these symptoms are the same as PMS.
We were trying and tracking pretty carefully, so I tested as early as I possibly could (12 dpo) and got a few faint positives in a row. Then a couple days later I went in for a blood test.