A negative result - 4 days until I'm due

Hi everyone
​Is it best to wait until after your period is due to get a more accurate test result? I did one this morning and it was negative...
​I've been having bad lower stomach cramping and aching back for over a week now and tiredness.  I don't have painful boobs but they feel fuller. I never get any of these symptoms this early before my period hence why I 'feel' pregnant. I ovulated on and had sex on the 16th & 17th of this month and my period is due in 4 days.