I feel for you! I'm introvert and I find it difficult to engage in social activity. Then again, I miss it like once in a couple of month and then when I think again, for the rest of the couple of month I'm minding my own business and being too tired and not interested in any social activity.

Don't be harsh on yourself! You've done your job being proactive. People have different aims and responsibilities so it's totally understandable that they can cancel meetings. I think that your friend who expressed hope that you would find someone else to go with showed care.

Have you expressed your feelings about being late for the friend who is always late? Some people just are like that, being late.
Hugs!