Hi.. am glad you have reached out to ask for help. relationships are a source of joy and can also be a source of confusion and angst for many of us. given what you have mentioned about the relationship, it would be important to understand what makes you doubt, what you are looking for, and how you see the future of this relationship. it also seems to be affecting your studies.
Next Steps
acknowledge that you are not sure what to do. expressing y our concerns with a trusted friend, who you think can guide you is necessary. acknowledge that relationship that you are in is only a part of you, you have other aspects in your life too like your studies, allocate time and emotional resources to carry on those tasks as well as well. you can tell the person with whom you are in a relationship that you need time to think and decide your course of action.
Health Tips
talking to a professional psychologist/counselor like me would help.