Is it ok to take take pregnancy 8 days after intercourse? me and my gf had sex on 1/20, her usual menstruation is on 24-27 so im worried i bought her a home pregnancy test and use it on 1/28 and the result is negative but im still worried cause i know 8 days is too early..please help me..i dont know what to do

 

and till now 1/30 she's not having her period. should take another test by now?? please answer