It looks like you have not been back since March 28. But perhaps you have notifications on. Or perhaps someone else might benefit.
What do you mean by background?
I guess I would say my role is just a preacher at my church I don’t really know what name to give it.
And I would say it’s a combination of what you described, I preach whatever God puts on my heart. I right out my sermons and usually end up getting flustered and just lose what I’m trying to say.
@The Liturgist asked some helpful questions. If you are preaching whatever God put on your heart, then it doesn't sound like you are in a liturgical setting.
His question about writing it out and getting flustered is helpful as well. Are you trying to memorize it?
It sounds like, if you haven't had much training, and are not in a liturgical setting, that you are likely in some type of simple Bible-oriented group of believers. What denomination, or faith tradition, if any?
My advice would be to focus on a single passage of Scripture each week.
@The Liturgist mentioned "expository" preaching. Going through a biblical text allows you to
a. Know what to study--the text, its background, etc.
b. Know the outline--the text itself!
You don't need notes at all if you can understand the various elements of the text, and then relate them as you go through the text verse-by-verse.
If you begin studying this out early in the week you can then think throughout the week about application. What does this text say that I personally need to hear? Are there changes I need to make in my life, based on this text? What does my congregation needs to hear from this text? How would I best convey that?
Since you are not writing out an outline (the text is the outline), or a manuscript, there is no need to memorize. By the end of the week you know what the text is saying, what God has said through it to you, and what the Lord has laid on your heart to convey to the congregation about how to apply it. Pray, put it in the Lord's hands, and tell people in your own words what God has shown you that week.
Even if you do not belong to a liturgical tradition, it may be a good idea to integrate Old and New Testament readings into your service. You can pick ones related to the text, or on similar themes. This helps people build a familiarity with Scripture, and also is a help to you, because it aids you in thinking through how other texts relate to the one you are focused on that week.
A concept I picked up from a Lutheran homiletics book, from a more liturgical tradition, also can go along with Scripture readings--make sure that whatever text you are preaching through you have "gospel content" in each service. People should not leave your church without hearing the good news of salvation in Christ. Some texts will lend themselves to this fully. For other texts, that may go through more theological, or practical lessons, it may be helpful to bring alongside other passages that relate this gospel content.
Finally, you might consider looking at some online lectionaries. Again, even if your tradition is not liturgical (the churches I have belonged to have not been), a lectionary can give you an idea of major texts and themes that are important to the life of the church. It can help you to not preach on hobby horses every week. You should hit the major events of the life of Christ, the life of the Church, etc. regularly, and a lectionary can help with that. It will also give related Scripture readings for you.
I still agree that the Lord can place on your heart whatever message He wishes you to deliver. And if He does direct you, by all means, preach nothing other than what He says.