If I had sex 25 days ago woukd a pregnancy test be accurate?

More than likely not. They usually are not accurate unitl about 40-50 days after. This is usually when you would start with pregnancy symptoms as well.

If it said positive yes, a negative could still be false. Need at least another, two weeks most like
Have you missed a period yet ?

I had a period 4 days after unprotected sex.. A Normal period...

Very very, did I say very unlikely that you are pregnant, there is and can be a very slight change but I would say not to worry at this point, again if you miss your next period, then wait a week and test then, But stress and worry can make a period late also.

So personally I would not worry about it since you had a regular period