Solitude is the choice to spend time alone. Unlike, loneliness or isolation, you actually enjoy these moments by yourself. Plus, being alone is critical for you to discover who you are, what you believe, and what you should do with your life.
Self-doubt is the little voice in your mind tells you that you’re “not good enough” to reach your goals. Everyone feels the pain of self-doubt at times. But it’s up to you if you decide to listen to it.