A quick google of metta meditation makes it sound likea lot of work. Maybe you should try something simpler. The "Men's Health" recommended meditation (I said it was simpler!) is just to sit cross-legged or in a comfortable position facing a blank wall and for ten minutes shortly before bedtime just do yoga-style belly breathing. Think of nothing, don't even count breaths. When your mind settles on something, push it away and focus back on breathing. I've only tried it twice, both times when I was already up too late, so too early to assess the effects.

It's supposed to reduce stress and improve sleep, but probably won't take you very far up the path to enlightenment.

Oh, for the dumbbells, have you tried doing the exercises standing rather than seated or on your back? That way the core stays at least partly engaged during the workout. It's a more natural approach since people seldom do any everyday activity that corresponds to a bench press.