is sustained eye contact across the lounge actually an invitation or am i making it weird in my own head

genuinely cant tell anymore and id like to stop second-guessing every glance. so heres the setup. couple sitting on the opposite curved couch in the lounge area, like 15 ft away. she catches my eye, holds it for what felt like 4 seconds (which in eye-contact time is FOREVER), smiles a little, looks away. then 2 min later does it again. he was talking to her the whole time so idk if he was even part of this. me f36 he 39, been in the scene 18 months so still kinda calibrating. my wife is convinced she was inviting us over. i was convinced i had something on my face. neither of us did anything and the couple eventually got up and left and now ill never know. heres my actual question tho... what does the eye contact thing actually MEAN at a club. like is the unwritten rule "if she holds your gaze you walk over"? bc that feels like a lot of confidence to extract from a smile. and what if i walk over and shes like "oh i was just spacing out lol". now we both look stupid. how do you confirm an invite from across a room without being the guy who misreads it. also btw my wife is like 1000% better at this than me and i think she might be mad i didnt act on it lol. so partly im writing this to get told im not crazy but partly im writing this bc i actually wanna learn