Hi Lonely123, I pray God's peace and joy over you. Although it has been a very long time since I was 17 or 18, I completely understand. I have also made a lot of mistakes and bad decisions because I did not want to be lonely. The biggest ones being, I did not wait for the Lord to prepare me for a relationship, losing/lowering my standards, not communicating with my mate, mistaking sex for love and never thinking about my expectations and the plans God had for my life.
I love that you are wondering about God's plan for you. There are many books that you can read to assist you in this quest, I would recommend; "The Purpose Driven Life". As far as relationship books, I would recommend "Knight in Shining Armour" and "A Good Man is Hard to Find Unless You Put God at the Head of Your Search Committee". The most important book though is the
Bible, read about Esther and Ruth.
As a single woman, whenever I get lonely, I think about all the ways that God has blessed me. Even though I wonder if the relationship that God meant for me passed me by because I was busy finding my own relationship(s), I am patiently waiting and expecting that God will send my Adam, the one whom I am perfectly designed to be his companion.
I want to encourage you to do one more thing. Have Faith and expect that He will bless you. You must speak things as though they already are. For instance Lonely123; if this is not how you plan to remain, you may want to consider a new name, like Expecting A Blessing 123
I almost forgot to say that you should surround yourself with like minded Christians and begin acquaintances, associations, friendships, ...... The relationship that is meant for you will eventually come.