How can I still smile when things go wrong?

I have for years hid behind my smile when things have gotten rough. And to a point I still do, but nowhere near the amount I did before.
I wish I could tell the people closest to me just what the hell's going on with me, but when I try I shut down, kinda like a clam, shutting myself inside the shell.
I dislike to argue, I don't mind bickering or such with my friends n' family, but to truly argue is something I really hate. A part of me go back to when I was younger, I see my mother or hear my fathers voice in the back of my head. I hear their words echoing. As I have stated before it doesn't even have to be me in an argument, if I hear one close to me I get scared. It's like I am just waiting for that hit or those words.

My "warning-center" doesn't really comprehend the logic in the situation, it's been taught that argument means to be alert and afraid. And it takes time to get passed it.
I have re-learned my "w-c" some things already, it doesn't scream at me whenever I enter a store anymore. The thoughts where overwhelming, my chest felt like it was shrinking, like my ribs where contracting into me. It felt as if someone was pushing a weight against my rib-cage. And it still do feel like that sometimes. Especially when I have to do something I haven't done before, like meeting someone I haven't seen or heard about before.

Right now, many things have gone bad, or maybe I should just say they didn't go as planed? I started school again, but since I screwed up with the application for my student loan I haven't gotten any money and as such I haven't been able to pay my rent, some days I barely eat anything because I don't really know when I'll have money to restock my fridge, freezer or my cabinet. And that is generally bad as it is, but lets add the fact that my body no longer even can pick up the nutrition it used to before the surgery it's even more important that I eat, and lets not forget I have to take vitamins, other medicines each day, but it's pretty much all gone and I don't have money to get a re-fill not right now. And I can't, or rather I won't ask to loan any more money from anyone, I'm already in much dept to my family that I'll feel even worse if I even asked again.
It was all supposed to get so much better when I moved and started school again. I had it figured out, thanks to the student loan I would be able to pay everyone back, even if not everything but at least most of it. And now I'm no longer in school and because of my "social phobia" I can't work. I have no idea how the hell I am gonna survive with any kind of pride left - then again I don't think I have any left, or maybe I have too much of it.

So, back to the title: How can I smile?
After writing this I can't understand how, in the beginning of this post I was going to say that I have people that love and care for me and that is true, even if my heart and brain doesn't always agree on that part, I do have people that love me and that I love. I have people that want what's best for me, especially when I doubt I deserve any of the sort. I do have people that will stand by me when things are rough, I just need to let them. I do have people that try to cheer me up when I am down and lends me a shoulder to cry on when I need it. I do have persons in my life that want me to be happy because I DO deserve to be happy. Even if I doubt myself about it more often then not. I can smile because I have them.
I can smile and laugh even when things sucks because I have persons in my life that love me just as much or maybe even more than I love them.

There might be a huge ass mountain between me and whatever there is that will make me truly happy and content here in life, so I'll just have to climb the F-ing thing and let my family and friends lend me a hand when I need it and be there to laugh with me about the smallest things when I fall and help me back up.

That is why I can smile even when things go wrong.