There's no trick to this. You need just the most basic training. Go running a few nights a week, and actually track your run. Stick RunKeeper or something on your phone, and you will notice a pretty drastic difference in a few weeks.
I started doing this about four years ago, as I felt similar to how you describe. Trying to run 3km just about killed me. But you keep at it. A couple of months later, I managed my first 10km run, which I did in just under an hour, and somehow I felt great afterwards.
Then do strength training. Nothing weird; nothing complicated. Just do squats with a barbell. Start with just the bar — it's 20kg alone.
And don't fall into the same trap that everyone does of being self conscious at a gym. Nobody cares about you in a gym, unless you try something stupid and dangerous like trying to bench more than you can manage.
I started doing this about four years ago, as I felt similar to how you describe. Trying to run 3km just about killed me. But you keep at it. A couple of months later, I managed my first 10km run, which I did in just under an hour, and somehow I felt great afterwards.
Then do strength training. Nothing weird; nothing complicated. Just do squats with a barbell. Start with just the bar — it's 20kg alone.
And don't fall into the same trap that everyone does of being self conscious at a gym. Nobody cares about you in a gym, unless you try something stupid and dangerous like trying to bench more than you can manage.