I would recommend going to see a gastroenterologist. Some people have bad experiences with doctors dismissing their problems, but it can be really useful to get tested (maybe a colonoscopy and endoscopy, some blood work, checking for parasites, etc. just to make sure everything is functioning as it should be). Also, you mention diet changes, but how long is it that you've stuck to your diet? Some people say it can take anywhere from a couple of weeks to a year to see any real difference in the odor after dietary changes. A good number of people have seen some success with paleo diet and FODMAPS diet. Some more things to try:
-probiotics (acidophilus or bifidobacterium)
-dietary enzymes (to help with digestion)
-kegel's exercises (to strengthen your sphincter)
Lastly, don't forget to keep your head up and remember that there are as many nice as mean people in this world. I'm 17 now and have had this problem for around 7 years of my life. Good luck!!!