Okay so for as long as I can remember I've had this issue where I forget to breathe properly when I'm very focused or concentrating hard on something like reading or writing or drawing or even just daydreaming.

I will notice I have been holding my breath for a while or only breathing once or twice every couple of minutes

After I've finished whatever I was doing I will have a bad headache and feel very tired for a while, especially if I was reading or doing something for a long time.

I'm getting extremely worried about this since its become a habit and is something I've been doing for as long as I can remember, possibly my entire life. Is this a sort of tick or something I could overcome and does this sound like something that could cause brain damage or other harmful problems? I'm kinda freaking out over here.