When is the best time to test for pregnancy and to get a definate yes or no if you last had sex?

on the 29th march 09 and you dont get periods so have no idea what cycle you are on or when you suppose to have periods?

Wait 4 weeks after the unprotected sex. Then if a week after that you havent gotten your period, test again, if it is still negative go to the doctor and get a blood pregnancy test.

It is hard to say as you do not have periods. If you really have no idea when your period is/would be, it is uniform to wait at least 19 days after unprotected sex. Lots of women do not notice that they are pregnant, so here are some points to look out for while you wait those 19 days.

Sickness and/or feelings of nausea
A strange, 'metallic' taste in your mouth
Breast tenderness, tingling and enlargement
The small bumps - 'Montgomery's tubercules' - on your nipples
Stomach pains
Tiredness
Constipation
Needing to urinate more often
Going off certain things, such as coffee and fatty foods
Increased vaginal discharge

Hope I helped and good luck.

if you haven't had your period yet then you are way too young to be having sex, sweetie! most likely, you need to go to the doctor. since it's been more than two weeks they will probably be able to tell you for sure if you are pregnant or not. also, if you see a gynecologist, he or she will be able to get you on some birth control, so there isn't any possibility of this happening again. trust me, babies cost a LOT of money, something someone your age really doesn't have. also, you should talk to your mom or older sister or aunt or someone about it so they can help you out with getting an appointment, etc. your actions do have consequences! don't be dumb about it, make the dude wear a condom at the very least!

A home pregnancy test probably wouldn't be accurate until at least 3-4 weeks after unprotected sex. Check the insert of the test you buy to see their accuracy rates.

your question doesnt even make sense!!