Dear Melissa,
Your question seems to boil down to this: if it is true that God will make it known to you if you have a religious vocation, then how come every time you consider religious life you feet the attraction towards marriage, and when you consider marriage you feel an attraction toward religious life, in other words, God doesnt seem to be making anything clear?
Melissa, it may be that you have unrealistic expectations as regards the way God makes the vocation clear to us and the time-frame in which he does so.
We have a natural and deeply ingrained inclination toward marriage, it goes with our human nature. Now, when we are baptized we become new creatures in Christ and this natural inclination becomes something deeper, it becomes a vocation, we recognize it as Gods plan, and hence our ideal for marriage and married love is raised higher because of Christs example of love in giving himself to redeem us and, consequently, its demands are also higher. But with Christ not only does the more spontaneous expression of love, married love, grow in depth, dignity and meaning; he shows us a totally new way of loving that involves the total giving of ourselves above and at the cost of mutual human love.
When God calls us to this type of love (the love a religious lives) he does not take away our human nature and sensitivity, so the natural inclination to physical love expressed in marriage remains, and we tend to see-saw back and forward between the two tendencies or calls. On the one hand we have our spiritual inclinations, grace moves us to generosity, and on the other we still have our natural attraction to marriage.
So, how can you tell if God is clearly calling you to consecrated love? How clearly does he call?
Some people, even from a very young age, have a clear sense of their call. Not that they dont have their ups and downs, but the do have a strong sense and conviction of what they are called to. Is this subjective sense enough to know there is a vocation there for sure? No, it isnt.
Surprised? Heres why not: the vocation is not totally subjective. The Church has to recognize it in some way for it to be real. The Church first of all tests and recognizes valid spiritualities and forms of consecrated life. Then, through the respective superiors of those religious families or Movements, she accepts the consecration of the individual members. So, for the vocation to become clear you have to have both elements, the personal desire or conviction about your vocation, and the acceptance of the Church through your acceptance into an approved spiritual family.
Many a young person who gets the feeling of a vocation on-and-off, or who has the conflicting attraction to both vocations (marriage and consecration) will not be able to get beyond that stage until he starts looking outside himself for an answer, because our subjective feelings and attraction are only a part of the formula, the needs of the Church and the prudent discernment of the signs by a vocation director, coupled with a good examination of how God has been leading you in your life, complete the picture.
It seems that God normally enlightens us as regards our call by using our own efforts to find out. This means that our vocation will not become clear until we take a step beyond our feelings and thoughts, and get some other input even if our personal feelings are strongly in favor of the vocation, and especially so if they are ambivalent.
So it is a question of looking into the community that attracts you, speaking to a vocations director, opening your soul to God in prayer, offering yourself to him, wanting to do what will most build the Church. In that way God will have plenty of channels through which to bring some clarity into your thoughts (and feelings).
And a final reflection as regards how clearly you should expect to see your call before acting on it. Dont expect absolute, mathematical security, and dont expect security that does not involve a strong act of faith and love. To perceive your vocation with enough clarity to start following it, it is usually enough to have the interest, the proper motivation, not to have any impediments, and to be accepted by the Church (i.e. religious superiors in the case of consecrated life, the bishop in the case of diocesan priesthood). To say yes and take the risk of trying on that basis requires an act of faith, trust and love. And that is one of the great beauties, one of the great miracles of a vocation.
God bless.