Embarrassing, but also worried. Small penis syndrome?

I am 21 years old, and 170 pounds, at 5 feet 4 inches. My penis is 3.8 inches erect, I always thought that was average, until I checked recently. Turns out I won the lottery, and managed to be in this tiinnny group of people. Even worse is that I've always held my virginity sort of close to the chest, and now it just feels worthless.

Well anyway, I don't know if I can go to a doctor for help. My culture, is super super sexually reserved and frowns on anything remotely related to romance, sex, or sexuality. My dad made me change the channel when the jimmy neutron valentines day special went on, and my sister got beat up for doing her sex ed homework. Honeslty, I don't even know if the doctor will be professional

I don't know what to do, and then even if i do go through with it, and everything works out, it might just be too late for me. I was not a late bloomer, my voice started dropping when I turned ten, and I was already growing facial hair. What the hell happened? And what do I do?

So, just filling out the additional details. I'm Sri Lankan, I don't know how long this has been going on, I only just realized lately, and one of my friends was complaining about his being 5.5 and was really shocked (but not rude at all) when he found out how small I was. I live in Canada now, it might also be worthy to note that I only ever had one small growth spurt when I was 11, and never grew past that. I also started masturbating from an early age, could that be why?