I am a student, how to get full attention on my studies, my other feelings makes me feel lazy n lack of interest in studies?

Get evaluated . Your symptoms can be caused by a lot of things including, habit, depression, adhd, and others. The only way to know is to get evaluated. Talk to your counselor or your doctor about your problems.
Discipline. It is human nature to feel lazy. But it sounds like you want to focus and do well in school. In order to do that, you need some discipline and time management skills. But it does not have to be so painful. First, sit down and write down all of your priorities, including how much time you want or need to spend on your studies. Then, figure out how much time you need to chill out and have fun.