Affirmations, which involve repeating certain words or phrases to improve well-being and self-perception, only work effectively when aligned with our self-concept. You can force yourself to say affirmations like, "I AM happy," repeatedly, but unless you already believe you are a happy person, this will likely do more harm than good. This can reinforce the very state you're trying to avoid.
Most likely, you're thinking from a state of sadness, trying to force yourself into happiness. The problem is that you're viewing happiness as separate from yourself and trying to achieve it through sheer effort. If you already believe you are a happy person, then affirmations can reinforce your happiness. However, every high has a corresponding low; extremes compensate for each other. As soon as you experience a happy state, you can expect sadness to arise eventually. To avoid extremes, we need to learn to live more naturally.
Our perception of reality is based on our perspective and how we view ourselves and the outside world. When we no longer identify with the limiting beliefs and conditioning patterns of our ego, we can shift our perspective toward a higher version of ourselves—our ideal self. These realizations help us shift our perspective toward our true self as we learn new things about the outside world and ourselves, and their relationship to each other.
Realization is a matter of feeling as a result of knowing. We must first experience something from our own unique perspective to gain a realization of who we are being. If we want to realize our true self, hidden within, we need to experience the knowing that this is who we are. This knowing comes from our being, not our intellect, because it is an essential part of us, not merely data or information from external sources.
We must integrate all parts of ourselves, including our unrealized true self, hidden within. What we are conscious of being is based on our perspective. With a higher perspective, we no longer identify with our mind and body as our sole selves; instead, we naturally become our true self—whole and complete.
As we realize new things about ourselves and the outside world, we naturally expand our state of consciousness. Our spiritual aspect guides us through this shift in perspective and perception, enabling us to realize more. This spiritual aspect, or "spirit guide," guides us in the 3D world because we are the "dreamer" unaware of our true nature.