There is nothing wrong with using your own words for prayers. No hard and fast rules when it comes to praying, just do it with a open heart and present your thanksgiving and requests to God. If you know one or two basic prayers like the Lord's prayer or the rosary, that would also be of great help.

Additionally, if you really feel the need, do try to read the Bible. Or, if you have the time, attend Mass, on Sunday's and also during the weekdays, liturgy of the word is part of Mass, there scripture will be read out for you to hear and listen. If you are not sure of what you read / hear, i suggest you ask questions or better yet, try going for Bible study classes. Your local Church should run at least one or two during the year.

and why do u feel any reason to feel insecure and afraid?

God bless!

If you are Catholic, you should have doubt.