Smoking before knowing i'm pregnant

I used to smoke cigarettes for atleast 3 to 4 stick per day but when i knew that i'm already 1 month pregnant i already stop smoking.. What i want to know is How can i be avail to flush out some of the nicotine i have in my body? I also feel some pain in my tummy specially in the morning.. as if i starve myself for 1 wholeday.