My friend making me choose between my other friends and my work?

You have to live your own life- you have so much going for you and sound like a smart person with a good head on your shoulders. Don't let him get to you. Maybe try to squeeze in some time to meet him for lunch or coffee, but it sounds like he is being very clingy, so just distance yourself from him. As they say, misery loves company and someone like that will just bring you down along with them. As hard as it may be to lose a friend, you have to continue studying and working towards your dreams.