Everyone stares at me? not in my head

I have social anxiety, so naturally I assume everyone is looking at me and judging even though I know its in my head, unless of course my acting up out of anxiety draws attention to me
But anyway, for a while now I've been noticing people staring at me, I assumed it was either in my head or I'm so worried about people looking at me I end up looking at others to see If they are and therefore start the whole thing, but I was out with a mate recently and walking round the supermarkets I thought I was getting looks, one guy walked past looking at me with a face that said I was a piece of shit and he was slightly amused, three other people gave me looks, and it turns out my mate saw them all too it wasn't in my head

Later when we were back at his having a fag out the front my back was to the road yet an old man stared at me the entire time he was walking past the house, when my mate brought my attention to it I turned and the man met my eyes exactly and refused to look away until he had passed the property, so even the back of my head seems to make people stare proving its not even a case Of me staring first

Iin? Anyone else had this? Really don't know what could be going on