Early 20's to mid 20's crisis. It's natural to have introvert thoughts about our lives at that stage, even if you didn't had them in your teens. I'd be more worried, if I were you, if you didn't had those thoughts.

And I have few friends who are like that - they have, what would you call, a "casual jobs", they study(or not), some have girlfriends, some don't and all of these have these thoughts : "what am I really good at?" ; "in what way do I change the world/contribute to society" ; etc. So it's fairly common and normal way of thinking at that age.

Thing about furry stuff - it is extreme, weird, unknown to these people, they don't understand it - and they don't have to. All of my friends know what I draw, what fetishes I have and so on. Every new person I meet, I tell them what's my side-job, hobby and that I'm oriented the most towards furry communnities. And many of those think it's weird, I'm yet to hear that it's sick. But, I think, it depends on the way you talk about it. I admit, that it's weird and sometimes it is indeed sick, but on rare occasions. I know that and I'm not afraid to admit to the fact that I'm weird, but talking about it can open new topics with people you meet, because everyone have their own sort of craze. I met a chick at the bar and we started talking, I've mentioned about furry stuff, she told me it's weird, but after a few drinks she told me about her kinks. And she also admitted to it that it's weird, that it's an abberation from the norm.
But, all in all - who cares? It's fantasy, nobody is hurting no one and if others can't understand that, then, IMO, something's wrong with them.

About not the "nobody understands me" thing. Dude, nobody has to. As long as they're tolerant about it, then I can't see any problem. Sure, it'd be nice to have someone around, in physical form, who could share your interests, opinions, etc. And believe me, you can find people like those. For example, I'm not much into furry fandom besides drawing that stuff for people and my own pleasure, but I met one girl who is interested in it too. At a concert, outside of the building, there was a group of people smoking and drinking, young stuff, 18-20 year olds. And there was this fat, unatractive girl. She had cat ears on her hood and since I was a little bit drunk I shouted "furry!". She got a mad expression on her face to which I replied that I draw that stuff and I'm pretty deep into it. And we talked for few hours, exchanged our e-mails, I've drawn a free picture for her, of her own fursona. So, you can meet people like that. If I may quote Masterplan's song "Soulburn" : "[...]the world is like a shining diamond, the way it glitters if you polish it right...". You just have to do your thing, take an aim and reach it, despite other's opinions. People like to put other of their kind down, especially my folk - it's a Polish shamefull specialization - jealousy and all that stuff. Thing is to have a dream, a goal and be honest about it - with yourself. Otherwise, the success is impossible. Or, if you're not honest with yourself about it - the effect might be something what you didn't expected, thus, it can taste bitter. You have to understand that despite we're a heard type of species, that we tend to live together in a groups and that we seek acceptance in them, we're also cappable to live on our own. And the geniouses and visionaries are quite often, if not most of the time, loners. Society drags you down, "pushes you into little forms"(another song from me) and overall, tries to make you fit into it. But there are more than those pre-made forms to work in life. And it all depends on you to find out how can you fit into it - or - live next or beside it.

As for girlfriends... don't worry. We currently have more girls than boys out in this world, so chances are, you'll meet someone sooner or later.
Be who you are or who you want to be and, believe me, chicks will get interested in you withouth all those pick-up games that people tend to play. ;)

And don't even think about suicide... especially at that age. Japanese warriors, back in 12th century, before era of shogunate and samurai's often killed themselves when they saw that they were aging and were saw that there'll be nothing better for them in life as a old fellow - I reccommend reading "Memoirs of the Warrior Kumagai" by Donald Richie to understand how their mind worked. And, since life expentancy vastly expanded since those times, you still have lot's of things before you. You just have to stay optimistic about it, despite all odds, and carry on.

thanks for your answer