Is it possible?

So I had my one month check up with my doctor and found out two things. First thing, I lost 5 pounds. I was thinking I probably had lost nothing since I was unable to exercise due to my back injury. Next thing, I have a hypothyroid. I knew the day would come since my dad and two sisters have it. Thanks a lot guys! But this explains why I have been tired lately. My doctor was shocked that I had even lost weight, b/c typically you gain. So now I have to take medicine for LIFE, which really sucks! But with this medicine, I should start to feel better and my metabolism will pick up.
I don't know if you watch the Biggest Loser, but I love that show. I just feel like I can relate to all those people who struggle with their weight. I have NEVER been skinny nor close to it. It has always been an issue for me. People who are skinny, just don't get it. We all have different issues and mine is weight. So I have been thinking about it. What would be a HUGE dream that would almost seem impossible to reach. And it popped into my head, running a marathon. Now I say that and think yeah right, those people who do that are crazy in the head. But if I set my mind to it and accomplished that dream, WOW, I could do anything. So, I must take baby steps, if I am even going to consider a race. In October my sister and dad are running a half-marathon. It would be awesome to run with them. So I am highly considering starting to train for that. We will see! I just must find the drive within me!!!!! Wish me luck!!!!