The Party Date

The Party Date has always scared, puzzled, and broken me. At least in the early stages of dating someone and they ask me to hang out with their friends in a party atmosphere I think my wires get crossed. Am I on a date or am I at a party? This situation rears its head in many different forms and my social intelligence gets fried in the process, do I pay attention to the date or do I make new friends and if I do will my date make new friends and then make a new date. This situation always happens with my date's friends. I don't think I've ever been invited by a date to a party where some of my friends are already there. I don't know if that would make any sense. What if I meet someone at the party more interesting than my date? Are there any kind of expectations when you get invited to a party and the person asks you to go with them as a date? If I meet a girl and we haven't gone on a date and she invites me to a party is that a date? Thoughts?