Hello I know where your coming from. Its so hard to tell if you actully smell bad to others when you are with yourself all the time, you tend not to notice.
What I have done in the past is after a long day wearing the same clothes for a long period of time. I took the items closest to my body like a t shirt & underwear and put it in a airtight container that had no smells left inside of it (like that plastic smell) Even a zip lock bag would work but make sure to air it out. Then put those items inside it. Then go take a shower, relax a bit to get the odor away from you memory a bit. Then go sniff the bag. Even take the items out and take a good sniff and that helped me pin point the sour smell of my body.