I assume your agreement is for 12 months ending in June? If so, and if there is no break clause, then that is the length of time you have signed up for. There's no legal requirement to have a break clause.
If you really do want to get out then tell the LL your circumstances and see if you can come to an arrangement. If you give enough notice then he/she should be able to find a replacement tenant. You'll still be liable for rent and other costs until a suitable new tenant is found though.
Technically, at the end of a fixed length tenancy you don't have to give notice at all, you can simply walk away, though it would be polite to give notice. You have to give notice if you're on a periodic tenancy.
Talk to your LL about your plans and see what they say.