I'm struggling with being in denial.
How does denial affect you?
I don't want to remember days that were awful
Yes, it's natural to want to forget bad times. But, it's very important to be open to all of your feelings whether they be good or bad. Otherwise, your mental health will suffer.
I need to work on it.
It's good that you're aware you default to a defense mechanism. It's OK in moderation, but remember: a goose that keeps his head in the sand for too long will smother.