Like the other post says, it's most likely your stress causing your sickness.
Morning sickness, if you were pregnant, doesn't usually happen for at least 3-4 weeks after conception.
Also, NEVER count on 'symptoms' to point to pregnancy. Many women never experience things like morning sickness or food cravings.
If you miss your next period, take a pregnancy test.
Good luck and Best wishes! :)
if you take your pill regularly the chances are slim even if he did go indside, if this is your first time having unprotected sex while on the pill, i'd say its more in your mind then anything, try not to worry too much or you will in fact make your self sick with worry... wait until the end of your cycle and see if you get your period, if not a pregnancy test might be in order. depending on how long it has been if your still within the 72 hour limit and are able to get to a pharmamcy before that time, get the "Plan B" emergency pill it will help prevent pregnancy. but you must be within that 72 hour mark otherwiise the chances of it working are very slim.... but like you had said your on the pill and take it regularly so i wouldn't worry so much...... take care hope i've helped