Yes, you were a monk, but not in one previous life, but in very many previous lives. Through good deeds you did in those and other your previous lives, now you have a good fortune and met Buddha's Teachings.
Now you can practise those teachings and find the true will of your heart this moment. Finding true will of your heart this moment is the highest realization, on which you have worked during many lifetimes, but still you have not mastered it completely in your previous lives. However, there are good chances that you could do that in this present life.
Also, your first life was not as a monk. Before becoming a monk, you lived many lives, doing many deeds, both good and evil. However, when you became a monk, you changed, and an immense amount of your previous bad karma was destroyed through your practice.
Every life you changed, and every moment you continue to change. Don't bother with previous lives: they passed and exist no more. Think of this moment: what is the wish of your heart now?
There was a time I dedicated my life to that cleaning: like a nugget of gold, covered with dirt, was my mind and my behavior. Every moment I tried to be in accordance with the original longing of my heart, keeping efforts to act as gold, not as dirt. With the help of other beings, including you in your previous lives, I was able to realize what the heart wants, and I try to not lose that realization since.
When I remain in that presence of the will of the heart, it gives rise to feelings of easiness and freedom, kindness and purpose.
I wish you the same!