It could be anything!! but it sound as if you worry alot and that can cause ulcers... and ulcer may or may not cuase Body Odor . I hate to keep telling you this but you need to see a doctor!!
Honesty, i wished i went to a doctor sooner then i did. Instead, i became more depressed and isolated myself from everyone. Then i started to obsessively and compulsivly worry about being smelly, at the same time, i did nothing to stop the smell becuase i didn't want to or didn't know how to. so i kept eating unhealthy, didn't excercise, negeleted myself and my health... Now, I am willingly ready to better myself and the way i smell by changing a few big things in my life and hopefully i'll get rid of this horrible curse i brought upon myself. i just hope you and everyone on here can find a cure for your Body Odor problems!