Breathing Manually

Hi I'm Neela, and I want some advice, opinion, or just any help from you guys.

After I overcome my fear of tightness in chest and shortness of breath by learning on how to focus on breathing and control them, I kinda forget how to breath automatically. I figured that sometimes I think I breath manually, and if I stop controlling my breathing I'm scared something bad will happen to me or I just won't breath. I know breathing is automatically done by the body and brain, but I just can't help it even though I try so much to focus my mind into other things. Which results, I'm not focusing when I do anything else and it's really tiring. It's like taking up 40% of my mind.

Can anybody please give me advice or help on what I should do? Thank you so much <3