My boyfriend is dying, and my friends act like it's not a big deal?

I cant begin to imagine what your going through and this amount of strain can be dangerous for you. Maybe try with family or tell your friends how you feel, they may think that by talking about him dying may make you sad. Try and make them see how you feel. Also if things get too bad look for proper and professional help groups online. If the problem worsens then you may want to find help with a therapist who will be able to help you. Good luck and best wishes.