I am with sAndaman here, the OP's boundaries were lax at best, dangerous at worst.
He may have been at uni but there is no way anyone could mistake him for being emotionally mature.

There is nothing dangerous in suggesting the OP sees her own behaviour was as equAlly unhealthy as the young guy in question.
There is nothing to be gained by pretending that sharing a room with someone, sleeping holding hands, with someone who is blatantly interested...No matter what words they are saying is not giving them the wrong idea.

It's equally as important that the OP takes responsible for her actions in this.

You can't just listen to what someone says and take it as given. You must look at their actions.

I challenge anyone here to say they wouldn't have recognised boundary issues when he started going through her phone and separating her from her friends.

He even said she was his!
How much more of a clue did the OP need.

No his behaviour isn't ok, but I suspect he is very confused, because he will be seeing her actions as contradictory to her words.

Be honest, apologise that things got confused, take up your part in this, say I shouldn't have done this or allowed you to share my bed.

But you absolutely must not contact me any more, Or my friends.
Return his gift. No its or buts, return it.

A knowledge he is in love with you, and you should have been more careful with A child.
Then block and do not reply, request your friends do not pass on his messages.
All the best for the future, pay closer attention to people's actions and not their words.