I think you're doing fine... You're body will tell you when you're tired and then that's the time to listen to it.... You're friends are just worried and not used to seeing you workout like this because you never did before and it's kinda shocking to them...
In a bit though you may have to increase the intensity of your cardio, doing hills or HIIT (high intensity interval training) for a change of pace...
The way to lose weight/inches on your stomach, arms and thighs is to keep doing cardio, to lose the fat, keep weight training to increase muscles. As you lose fat the muscles will pop and voilą lean trim arms, thighs, stomach

not THAT easy of course, but you know what I mean
