How should I go about studying? I feel a lot of shame.

I am a 24F and I really want to overcome getting my GED after years of shame.

My story is that my parents weren't around for me very much, so I had to raise myself and start working at a very young age. I hold a lot of shame and even bitterness because I wish I had a normal experience.
I haven't studied properly in years. I tried taking my test a few years ago and didn't pass. I felt like I put in my all but was deeply disheartened when I didn't get the scores I desired.
I struggle with reading comprehension and reading in general. Everyone says they I should go test for dyslexia with how my brain works. It takes me a while to read and write and understand. I try to sound smart but I don't think I am.

I started a bank teller job as a branch I was told is super slow with lots of down time.
I think I am going to express I am studying but I feel embarrrassed to tell my boss.
What are some ways I could study and not feel shame while at work so when I'm home my workload isn't as much?