If I had a baby in October and didn't get my period until the 1st of march and it ended on march 15 which lasted two weeks, and did not have sex during that time, but I took a pg test on the 6th of April and it came up negative then took another on the 9th and it was positive how many weeks am I? And I just experienced implantation three days ago... my mom says I'm 5 weeks

We really can't tell you. It all depends on when you ovulated, and unless you've been taking your basal temperature for 6 months tracking ovulation, there's no way to know. Doctors go by your last menstrual cycle. If your last menstrual cycle was March 1, that would make you 9 weeks pregnant. Pregnancy is calculated from the first day of your last period, and is based on the average woman's cycle and ovulation date.

If this is a question of paternity you should know that due dates are a best guess, not an exact science, and only a DNA test will show paternity.

Good luck.

I didn't have sex with my fiancé until the 17th of march and a lot after that, so do I go off the pregnancy test that was finally positive on the 9th of April and wouldn't that make me two weeks at that time and 5 n half weeks today? I haven't had sex with ayone else so there's no need for a dna I never said I slept with anyone I just wonna be close because I know I'm definitely not 9 weeks.

Would an ultrasound know?

I didn't have sex with my fiance til the 17th of march and alot after that, so do i go off the pregnancy test that was finally positive on the 9th of april and wouldn't that make me two weeks at that time and 5 n half weeks today?? i havent had sex with ayone else so theres no need for a dna i never said i slept with anyone i just wonna be close because i know im definitely not 9 weeks.

We can only go by your last menstrual period. That's how a due date is calculated. Obviously you didn't get pregnant on the day you got your period. You may have ovulated earlier or later than the average woman, especially since you recently gave birth, and this was your first period since giving birth. Unless you know exactly when you ovulated, like I stated in my first post, there's no way to know exactly when you conceived.

Pregnancy is calculated based on the first day of your last period. You stated that the first day of your last period was March 1, 2013. According to this pregnancy calculator:

http://www.google.ca/url?sa=t&rct=j&q=pregnancy%20calculator&source=web&cd=1&cad=rja&sqi=2&ved=0CEoQFjAA&url=http%3A%2F%2Fwww.babycenter.ca%2Fpregnancy-due-date-calculator&ei=J4eFUeD3FIK4iwLYiYD4Aw&usg=AFQjCNF2coy0tBfsWcYDPGCJ7s5leQ9PzA&bvm=bv.45960087,d.cGE

That puts you at 9 weeks, and the estimated due date is December 6, 2013.

would an ultrasound know?

An ultrasound is also a best guess, and can be off by 2 weeks either way.

There is no possible way to know an exact time and date, at the very best, they are plus and minus a week.

So stop worry about when you got pregnant, and if you are 5 weeks or 6 week or what ever.

Latter on they will decide a due date for delivery, which will be plus or minus a week or so also.

Start thinking about ready for baby and not worry about which night it happened.