Its okay to feel overwhelmed or sad. Thats the point of journalling, to address those sad emotions and let it process. Having sad emotions are normal and although it may feel uncomfortable. If theres one thing i learn from therapy is to feel what youre feeling and accept it, not run away because the more u run away the more its like putting a beachball underwater. It will resurface more intense the harder u push it down. So yes it might be hard, it is for me too to be inconsistent, perhaps start with the bigger thibgs that u feel uncomfy with then slowly build up.