Your thoughts create emotions. Your emotions have a vibrational frequency. To create the life you love, your base emotional frequency needs to be at 500 level, aka the level of love.
You can say no to a thought. You can choose a new thought.
To become aware of your thoughts, take a deep breath and notice what you are noticing. When you catch yourself in the low level emotion/feeling (physically it feels like a contraction – tightness in chest, shoulders, jaw, shortness of breath, heaviness in belly, etc.), take a deep breath and choose a new thought. Chose an expansive thought/feeling. Choose love.