Just take it really, REALLY slow. We like to tell ourselves that it has to be all or nothing, but 10 minutes, even 5, can be a catalyst to a whole new life if you just believe and commit to it. There are people all over this site who started with 10 minutes and ending up running marathons & more. Very inspiring. I hope you're reading "success stories" on here because they're SO helpful to keep your motivation high. Also there are a WHOLE bunch of workouts you can do on here that are just 10 minutes, many that don't even require any equipment.
Good luck with your weight loss efforts!