Hi, yes I can understand how embarrassing this must be for you. But please don't let your mood down for a problem which is genuine and rectifiable. You need a speech therapist as it takes certain mechanism to learn pronounce letters and words. The counselor/speech therapist will show certain tongue exercises which can help you pronounce all the words and letters in their phonetic nature. You can use the practo search engine to find a speech specialist or you can also inquire with a counselor who would know speech therapy.