Hello, Aji, and welcome!

That's a tremendous undertaking, adapting to a language environment so different from your own. I admire you. My own experience, going from one European language to another, was not nearly so extreme. There were, however, a number of sounds I could not distinguish in speech. At first, I often mispoke or misunderstood. My only practical advice is to avoid others who share your mother tongue. Immerse yourself in English. Speak only English, read only Enlish and liisten only to English. You will get a lot of headaches, and your brain will stop working at the end of the day, but you will learn to distinguish the sounds you are having trouble with. And please, stay with us on the board.