Sometimes we just know. Sometimes it's a process, the spirit revealing and enforcing something throughout the years for us. Sometimes we don't know something.
I comfort myself with this:
"If I speak in the tongues of men or of angels, but do not have love, I am only a resounding gong or a clanging cymbal. If I have the gift of prophecy and can fathom all mysteries and all knowledge, and if I have a faith that can move mountains, but do not have love, I am nothing. If I give all I possess to the poor and give over my body to hardship that I may boast, but do not have love, I gain nothing.
Love is patient, love is kind. It does not envy, it does not boast, it is not proud. It does not dishonor others, it is not self-seeking, it is not easily angered, it keeps no record of wrongs. Love does not delight in evil but rejoices with the truth. It always protects, always trusts, always hopes, always perseveres.
Love never fails. But where there are prophecies, they will cease; where there are tongues, they will be stilled; where there is knowledge, it will pass away. For we know in part and we prophesy in part, but when completeness comes, what is in part disappears. When I was a child, I talked like a child, I thought like a child, I reasoned like a child. When I became a man, I put the ways of childhood behind me. For now we see only a reflection as in a mirror; then we shall see face to face. Now I know in part; then I shall know fully, even as I am fully known.
And now these three remain: faith, hope and love. But the greatest of these is love."
Even Paul, the author of much in the New Testament, says that "we know in part and prophecy in part" and that "even if I have all the knowledge and faith that can move mountains, I am nothing without love". So I keep myself simple. If I don't understand something, I simply ask God to teach whatever I need to know in His perfect time and ways. Meanwhile, I can trust that He is God, He knows when I don't, and I can rest in Jesus Christ, draw strength from Him, even faith from Him, and I can love my neighbor with a happy heart. If there is something that's confusing me and I need to know it, in time I will know. I shouldn't trust too much on my own feelings or supposed knowledge, especially if I'm prone to running around, afraid of everything in confusion, not content in letting God to guide me. Many suicide cult leaders probably had great assurance, and some of them were probably very sure about what they "knew".
Another one of my favorites, perhaps my favorite part of the Bible:
"At that time Jesus said, “I praise you, Father, Lord of heaven and earth, because you have hidden these things from the wise and learned, and revealed them to little children. Yes, Father, for this is what you were pleased to do.
“All things have been committed to me by my Father. No one knows the Son except the Father, and no one knows the Father except the Son and those to whom the Son chooses to reveal him.
“Come to me, all you who are weary and burdened, and I will give you rest. Take my yoke upon you and learn from me, for I am gentle and humble in heart, and you will find rest for your souls. For my yoke is easy and my burden is light.”
You will grow in faith, you will grow in knowledge. Leave it to God, ask for Him to guide you in faith and wisdom. Don't try to outrun God, don't run around scared all the time, you will learn patience. He can be very thorough when He's growing us in spirit. He's not slow, He's thorough, and He knows that if we got everything right away, we'd lose most of it the next day, without understanding what we had in the first place. So if something takes time, let it take time. Read your Bible, ask for guidance, pray as you are, believe that Christ came for you too, and He's more than willing, more than able to help you with these things. Said a prayer for you. No fear.