Dear Kevin,

I won't be able to give you an exact answer to your question. If it is confusing for you to figure out, just imagine what it is for someone who doesn't know you trying to look in from the outside. All I'll try to do is to touch on some of the possible reasons, and you will have to draw on your own knowledge of yourself in order to figure out which one or ones apply in your case.

Sometimes these reactions may be due to a nervous temperament. If it is a new environment and the first time away from home, or your first silent retreat, this can play on our temperament and cause undue fears and doubts.

It could also be that you did not know what to expect, and so the experience overwhelmed you. Sometimes it is a moment of truth, and we are faced with the stark reality of the vocation, its totality and definitiveness, or the stark reality of our weakness and all we need to give up if we are going to follow a vocation.

There may be many other reasons as well - the externals of life in the seminary (prayer, discipline, schedule, the commitment of the seminarians, etc) that hit us hard.

The important thing here is for you to reflect yourself and get beyond the experience of fears and doubts to touch the truths that God is helping you discover through these experiences and reactions.
 
God bless.