your friend is big enough to look after and mingle herself.

your responsibility ended once you both entered the party, you did not sign up to entertain her all evening did you?

you need to talk to your friend, it could be she did not have time for a big goodbye, especially if the person giving her a ride home was wanting to leave quickly. She probably didn't want to keep them waiting or was scared they would leave without her.
she may be a bit jelous of the attention you were getting, in that case an honest explination about you not liking how you behave is may be necessary. but whatever if she is a good friend she and you will only be able to work things out if you talk to eachother.

sounds like you could be depressed, have you talked to your doctor about your crying and how you feel? he may be able to prescribe some meds to help you feel better.

having things to look forward to involves planning, these things do not have to be big parties or even involve going out, a bar of chocolate in the kitchen cupboard could be something to look forward to, or a show on tv.

All i have to look forward to these holidays is... to visit my late partners grave on Christmas day, and a DVD I bought myself last week which i will save till i begin to get lonely (probably about Saturday) but most of all i look forward to the holidays being over so my routine can get back to normal and i will see people again.

if you do tend to draw attention to yourself at parties, your friend will probably know this already before chosing to ride with you to the party. it was her choice, she could have declined the invitation or ride if she wished to.