Dear Bart,  

Maybe you feel lost because you don't know what to do or where to turn with this thought of the priesthood that has come to you - but you have to remember that your feelings are only part of the picture. 

You are not lost because you are not on your own. The thoughts that come to you about the priesthood, the desire to become one, came from somewhere else, or rather from Someone else, and not from yourself.  

How can that be true if you know you are really thinking them, and you are not hearing voices? Well, Jesus tells us that we can do nothing without him. St Paul said even more specifically that we cannot say the name Jesus without the Holy Spirit. Much less think of giving our whole life to Jesus as his priest. So He is the one behind these thoughts.  

So now the first thing you have to do is stay close to him, and especially trust him. You are dealing here with God, but God who is very close - so close that you receive him in Communion, and so close that he can speak to your heart (like in your attraction to the priesthood) almost without you realizing it is him.  

Make sure you go to Mass often, and receive him as often as you can in Communion. This is where you are going to get most light from as regards figuring out what he wants you to do, and where you will get the strength to always do what is best. And say a prayer every day to Mary for her help. It doesn't have to be a long one, but just every day: 3 Hail Mary's for this intention will make a huge difference. If you pray the Rosary offer up one decade with this intention.  

Being that you are still in high school, it would be good to bring your parents into the picture. Their advice will be helpful, especially if they are practicing Catholics, and because of your age you will need their OK if you are going to take any practical step toward the vocation while you are still in high school.  

It would be good to talk over with them what your next step should be, to see with them if you should look for a high school where you can finish off the years you still have to do and at the same time prepare yourself for the seminary (sometimes these schools are called high school seminaries, or apostolic schools, or some other name), or if you should finish out your high school at home. 

The answer to this question will depend to a certain degree on your age and grade, and the type of school you are in. 

As you think it through ask yourself questions like: will the friends I have now be helpful for me towards following a vocation? Am I doing as well in school as I should? How am I spending my time?  

Another thing to have 'on the burner' is the type of priest you think you should be. What does God seem to be attracting you towards - service as a pastor in a parish? Missionary? A religious congregation? Contemplative life? The answer to this question (even if it that you don't know) will be of help to you as you start looking into it more, because God has a concrete path for you, and he will make sure you get enough hints to know what it is. 

I hope this gets you started, or at least helps reduce your confusion.