Poor OP. I used to be just like this when I was a wee lad. Women would just approach me and start talking to me and I'd be all weirded out that someone randomly came up talking to me....

"Hey, do you remember me from (some random thing I had never done)?"

"No, sorry about that - you must have me confused with someone else". End of conversation, sip drink, walk away.

The first time I thought "that was odd". After like the 4th time in a year I was like "waaaaait a minute, I am a fuckin idiot". Oh well, live and learn. There were definitely a couple of smokin' hot opportunities squandered. Damn, I still remember what some of them looked like too.... bites knuckle

Better luck next time OP. Protip : the hair touch is often a huge giveaway if the hair is otherwise well kempt; along with the hand lightly caressing the chest/collarbone area, look for cues like smiling, widening eyes when they look at you (watch closely - the pupil will enlarge if they are interested). Body language is important too. Leaning in is a good indicator, open shoulder posture (ie - arms not folded, shoulders are more open and relaxed). Sorry this is really hard to describe through text, but I believe in you, OP. You can do this; if you choose to.