thumping/ knocking noise. please help!

[NightProwler13]

so it all started early summer, when i noticed my car ( a 1989 240sx coupe) would make loud thumping/knocking noises that sounded like they where coming from the transmission/driveshaft. it only did this after agressive driving and would go away eventually. now its only gotten worse! it does it all the time from 5 mph - 25 mph and is so loud it is heard from the outside. i noticed that as i pick up speed so does the knocking sound. also when i brake i hear this creaking sound at times.

i have checked my car for things stuck on the drive shaft and what not. i have asked other fellow 240 owners, and i HAVE SEARCHED this forum and i cant find anything that helps sole this problem. does anyone know what this could be?? how to fix it? i am sick of hearing this noise and am worried that i am seriously doing damadge to my car since it is my daily driver. any information id greatly appreciated.