How dark and how large your nipples get will depend on your racial background and just how you are as an individual - no-one can predict this for you. The little ring of dots/bumps on your nipples around the centre will also become larger and more prominent. Asking your mum *her* symptoms may give you a clue as to what you can expect.
While some women don't experience symptoms until weeks or even months into pregnancy, others start getting symptoms within a few days.
Have a look at the links below for more information, and personal anecdotes of women who've felt signs of pregnancy in the first couple of weeks, before their next period was due.
Personally, I didn't get morning sickness that early (hardly got it at all during pregnancy), but I did notice increased breast tenderness and swelling within 3 days of conceiving my daughter. I experienced some breast tenderness after conceiving my 2nd child, too, but as I was still breastfeeding, it wasn't as noticeable, or as early. Maybe 1-2 weeks after conception.
You can test a week before your period is due with some pregnancy tests, but in my experience they're much less reliable that early. (Even though they claim high reliability). Browse the tests for sale at your local chemist, and check the details on the boxes!
There is no 100% guaranteed sign of pregnancy except a baby coming out! Some women (especially if they're very obese and have irregular cycles) honestly don't notice any signs of pregnancy until they're in labour. Some women never get morning sickness, don't notice the baby kicking (though that's rare), are too big to notice the weight gain, and some have occasional spotting or bleeding despite pregnancy, that they mistake for their period.
Get a pregnancy test 2 weeks or more after sex, or when your next period is due, whichever is later, for the best chance of being *sure*. In the meantime, have fun reading the links below and keeping your fingers crossed! :)
:)Bronwyn