Hello~You may be deficient in the mineral, "Zinc" a zinc deficiency can cause very odd smelling body odor. Ask for a test to determine if you are deficient in this mineral.
Hi liiiii- if you have a general practitioner they have some prescription strength deodorant you could ask for. There also might be either an infection in your kidney or pancreas so a full blood workup would be in order. See a doctor have him take a swab of your underarm. It also could be a reaction to some food or medication. See a doctor for best results.
So sorry that you are having some issues with strange smells, I'm sure that is not fun to deal with. How to find a doctor depends on your situation- do you have insurance? If you do, you can look up your insurance information and find a doctor there that's covered. If you do not, maybe you can ask family and friends what doctor they recommend? If you are in the US, there are many urgent care places that you can go to for an appointment and they can recommend steps from there. Good luck!