Hi! I think all your reactions are normal. I think people who experience things that others don't must be sensitive and considerate towards others when mentioning those things. That's why I don't like Facebook especially on holidays and social occasions. People like to brag about themselves, unfortunately.

About the volunteering, maybe it's just a short phase because he is new there, but the organizers must also be sensitive about these things. There is no warrant to recognize a male volunteer more than a female volunteer, unless maybe he contributes financially to the organization and they have to recognize him for that.

Money and trips don't buy happiness. They are nice, but not necessary, in my opinion (you may or may not agree). Your friend probably is not as happy as he appears. We always show the good side of ourselves even to friends. There is always a dark side that we hide, because no one wants to know about it.

It's not always your fault what you feel. Others take some responsibility.