Welcome!
First off, try to figure out where your motivation is coming from. Then use the heck out of it.
Start by taking baby steps. Don't try to jump into a workout full blast. One method you could do, that I'm going to do myself, is walk in place for 30 mins to an hour while watching television. Don't even need a treadmill.
You can also try stretching exercises, like pilates or yoga to build yourself up to it.
Once you start doing that, and changing some of your food habits to moderation, then you'll definitely start feeling better.