Sometimes two people who are involved with each other are having a very different time. You were clearly attached. He wasn’t in the same place. As painful as it is to be rejected, he has done you the favor of ending it before you became even more attached when he wasn’t. It would have been so much worse if he had strung you along and then left you after a year or so.
Although it may feel to you like you’re doubting everything due to the break-up, I have another perspective. At 18, it is normal for you to be concerned about your future. Decisions about university, career goals, and what directions to take toward your future can feel huge. For many young people, becoming 18 is fraught with meaning. Are you an adult? Are you really ready to be independent? Do you have a direction? It can feel as if you have to make the absolutely right decisions. Planning a future with the boyfriend seemed to settle some of those questions. You were under the illusion that you didn’t have to think about your own future because you were thinking about a future with him. For many young people, that’s a relief.
But here’s my wisdom for the day: You have plenty of time. You don’t have to decide your whole life now. You do have to take a risk and do something to claim your own adulthood — not as part of a couple but as your own full self. That is what will build your self-esteem. That is what will eventually help you find a partner who is also a complete adult.
I suggest you seek out a favorite teacher or other adults you trust and talk with them about the decisions they made at your age and what they learned from doing so. Ask those who know you well what they think are directions for you to take. Then do something to start getting off the farm for awhile. You may eventually decide that farm living is actually something you like. But you will be more committed to it and will be more successful at it, if it is a clear choice rather than something you do just because you are too afraid to try anything else.
I wish you well.