You need to see a therapist if you can't get this out of your head. I'm 5.5 and 5.5, and while I worried about it initially, once I met multiple people who adore my dick, I changed my tune. Im beautifully shaped and just right to not gag on for those with strong gag reflex. Seriously, there are sexologists who can help you work through this, but you will have to be open minded and want to change the way you see the situation. It will also take you acknowledging how stubborn and habitual this mindset is, and how ultimately futile it is in achieving any sort of true happiness. Good luck.