What choice do I have?

I cannot tell you how many times someone says to me, "You have an amazing attitude for everything you've been through!" or "All of that and you seem so happy." What am I supposed to do - curl up in the fetal position and wait to die. I appreciate the encouragement, don't get me wrong, but what choice do I really have?
This is how I see it: I could wake up every morning, in pain/nauseous, and hate my life, be pissed at the world and never leave my bed. Or I can wake up in the morning to a day filled with the love of my family, the support of my friends, and choose to be happy about my life - as is. I get to stand up on my own two feet everyday. I can spend my days caring for my son, and many other things that more disabled people than I could only dream of - there are soooo many people out there much worse off than me. So, I don't really see the choice. Its up to me to see the good in my life or otherwise I would be pretty depressed most days. There are days I am not happy with life, or cannot get out of bed due to pain, but every time my son smiles or my husband gives me a kiss I remember that I am one of the lucky ones.
I truly believe everything happens for a reason. I don't know why I have spent my life in pain, dealing with a wide range of symptoms, or had multiple surgeries - but, I find meaning in it all. In some ways all this has helped me to appreciate the smaller things, the good days, and the little moments of true happiness in my life.
Next time you wake up in a bad mood, or you're sitting traffic pissed off at driver in front of you - remember there is someone out there having a much worse moment than you. Take the time to realize happiness is what we make of it. If you see you're life in a negative way, happiness will be hard to find.