Concentrate on chin ups, squats and military presses. Keep a journal and just try add one rep a session then add the smallest weight incriment and try raise your reps again. If you can do atleast one chin or pull up then start by doin 10 reps, nevermind they are all singles and add 1 rep every workout, i did this when i first started and your strengtg will progress quickly! I day1 militarys, day2 squats, day3 chins day4 rest day 5 repeat. Short simple workouts just going for strength til you improve your work capacity then you can add more movements. As for being tired, lazy etc you must keep active, go for 1hr walks every day, get as much sun as you can, anything not to strenuous, it will get your bidy in the mood to move and help you recover from your resistance training. Good luck and dont forget food is fuel!