Love hurts ! It does sometimes but it also can be awesome.
Okay...let me tell you first of all that I am an old lady...I am 60 something and that is most likely ancient to you. But I do remember being young and feeling what you are feeling. Can I tell you now that you will feel this many times over?
You are giving your boyfriend a whole lot of power and control over you that he probably does not want. There is some stupid saying about holding sand...if you squeeze too tightly...the sand leaves your hand. But if you hold it gently, you can keep holding onto it.
When you say things like you can't let him go or you couldn't handle if he broke up with you...I worry.
Do not let this experience make you feel sick or depressed.
I am going to suggest things you may not want to do but...you have to find focus in other things outside of this young man. He will enjoy you more if you are not so focused upon him each and every moment.
Let him come to you. You must be prepared that he may choose to go. Allow him that option and I bet he will come to you. If not...it is better that you know now and can move on.
You have so much life ahead. He may be the one or he may be teaching you things for your future. Remember this time...it goes so very fast.
We are here for you so use us wisely. We have lots of experience.