Why am I so afraid of eye contact?

it stems from your upbringing

That's quite common in introverts, those on the autistic spectrum, or anyone who lacks social confidence. A little tip is to look at their forehead or right between their eyes and it will look like you're making eye contact.

It's about lacking self-confidence or never learning how to do it.  Making eye contact with someone else is very uncomfortable for many, so you're not alone.  

You can learn how to do - when to look at a person, when to look away and when to blink your eyes.  

It's all about getting comfortable with it or accepting that sometimes it'll be uncomfortable, and that's ok.

Neither. I think you just need more time to master the art of eye contact and all you need is confidence and that's easily achieved when you accept that the other person is no better than you.