Commonly, when people talk about discerning their vocation they are talking about the religious life. Should I become a priest? Maybe just a brother? If you are a female you may ask, "Should I be a sister?" Which religious order? Do I want to be in an order or do I want to be a diocesan priest? The other option besides being in the religious life seems is the married life. Do I want to get married?? Well, in my personal opinion (as in--this isn't dogma, and I realize that it can probability be torn apart theologically and you can believe what you want) is that there is a third vocation--that of the single life.
Now, I realize that the argument against this third vocation is because because you do not make vows. You are in more of an in-between state of life. If you enter a religious order, you take vows of celibacy. If you become married, you take vows to be faithful to your spouse. But with the single life, while you are presently chaste (or SHOULD be chaste) celibacy is not permanent necessarily.
I know too many people though who are single and potentially will remain single. Some of them seem perfectly happy remaining single but don't belong in a religious order. Some of them would prefer to be married but can't seem to find the right person. Others, are struggling and still trying to decide whether they should be religious or married. Whether it be a transitional or permanent, I don't think it's fair to say that it's not a vocation.
Again--that's my opinion. I'm sure the argument would be that a vocation is a permanent state in life. That is not my point. My point is, that I think the single life should be looked at as a vocation, whether it be transitional or permanent, because every day we need to try to decide what God wants us to do with our lives. We should always try to trust in God and try to do His will as opposed to our own. It may not seem fair. We may feel lonely and want a spouse to spend our lives with. We may want children. The fact that you can't pursue the goals that you want may make you angry at God. We need to step back and say, "not my will, but your will be done."
I'm not going to say that your life will be easier. You still may have a lot of suffering in your life (that is a post for another day). I am saying that by putting aside what we want in life and doing what God wants us to do with life we will be closer to him. Remember that everything we have, our very life and existence, is a gift from God. Should we not be doing with that life what He wants us to do?
If the single life is your vocation please remember that you are never alone--especially if you are pursuing God's will. God is with you. God loves you. Rejoice that by being single you are given the opportunity to spend more time with God getting closer to him.
Now, you can feel free to let me have it. Am I an idiot of thinking of the single life as a vocation??