We All Feel Empty Sometimes.
Every day we encounter different types of thoughts, some are positive, negative and sometimes we cannot feel anything! And it is an unhealthy feeling that we encounter on a daily basis. I myself suffered from this issue for a long time and if you do not solve it, it will grow with time and become much worse.
In my case, the root cause of the problem was because I want to do many things in my mind and I know that I will be happy and satisfied if I start pursuing my ideas, but unfortunately, I was not able to do so for many reasons, university, family work and much more.
The solution to this problem may seem trivial, but believe me, it is so effective. You just need to follow the voice in your brain and start doing what you want. We all have 24 hours of days, and you have the choice of where to spend them. And also you need to define your priorities about the tasks that give your life meaning and joy. Studying is important but if your mind is obsessed with another idea and you cannot get it out from your brain, then believe me you will not focus on your studies and also will not pursue and turn the idea into a reality.
To conclude, do not feel that you are the only one who suffers from this issue. Life is just a combination of ups and downs and you just need to figure how to deal with the downs and you will be alright.