A - Thanks for the question. First for a few definitions:
Vocation = A call from God.
Discernment = The process of finding God's will by listening to and obeying his call.
I know that discerning God's will for your life can be quite a tangled mess sometimes. I can't tell you what you are called to, nor can anyone else. But, a spiritual director might be able to help you sort through what is going on. Here is Fr. Thomas Dubay on what it is all about:
"What, then, is spiritual direction? It is the guiding of a person into a life truly under the dominion of the Holy Spirit, who is the primary director. It helps the directee to be more and more docile to the light and promptings of the divine Sanctifier, identifying impediments to this, as well as ways to overcome them, giving instruction and encouragement in living a life of virtue, and assisting the directee to advance on the path of prayer — the road to union with God."Sometimes we can't make heads or tails of what is going on in our own lives and a spiritual director is able to take a more objective view of whether what we feel and think are from God or not. Here at St. Mary's we are blessed to have many spiritual directors who regularly see over 200 students to help them. I suggest you contact one of them.
Now, as to your question - I don't think it is strange that you are feeling a different calling. The process of living out a vocation can be seen in layers - some of them need to be discerned and others do not.
Some vocations that need not be discerned - the vocation (call) to holiness, virtue, chastity, etc. All are called to these things.
Some vocations need to be discerned, for instance - the call to married life, religious life, or priesthood. Lower-level kinds of decisions should also be discerned - where should I live, what should I study in school, who should I be friends with, etc.
When we talk about vocational discernment in the Catholic Church, we usually focus on the big issues - marriage, priesthood, and religious life. These are life-long commitments once a vow is taken or ordination happens. Once you take a permanent vow or are ordained, you need not continue to discern whether you are called to that life, you just need to live it out the best you can.
But, up to the point of getting married, getting ordained, or taking final vows - the process of discernment continues and a call may not be what you think it is.
I hope this helps. I will pray for your discernment.