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Then you are about 6 weeks pregnant, meaning you're in the first trimester :)
Second tri starts after week 12
If you count the weeks from the first day of your last period, that's how many weeks you are. A pregnancy is technically defined as 40 weeks from the first day of your last period. Trimesters are exactly what the name implies so you take 40 and divide by 3. 40/3=13.333 weeks. The first tri is 13 weeks and 2.3 days long, second trimester lasts until you are 26 weeks and 4.6 days and the last tri takes you to the finish line of 40 weeks.