Not baby related

Has anyone been away from there love one and they go hurt really bad and they'll tell you it's ok that your no there? My Bf cut his fingers pretty bad but I'm about 300-400 miles maybe a bit more away because I have school and I wanna go to him I feel my teacher would understand but he keeps telling me that I need to stay school more important and idk if it because of all my hormones or just normal I feel like I'm a horrible person for not being there. I know there nothing I can do and he fine overall besides being in severe pain. I need to stop beating myself up but how?