fast circuit
try circuit training...
get a couple of good exercises and throw them together for a full body work out
squat
bench
chin up
swiss ball crunch
romanian deadlift
now, set your time limit, nothing more than 45 minutes, lets say your going to go for a half hour
squat about 70% of your max for reps and stop just before you feel the burn or fatigue
wait a minute
bench (the same way u did for the squat, 70% stopping before fatique)
wait a minute
chin up (the same as before)
finish the exercise, rest a minute then start all over
this will keep ur metabolism FIRING and ur muscle will be built up without burning out, do this three times a week and not only will ur strenght improve but u will be a cut piece beef in time for summer. the most important thing is to listen to ur body, dont tire urself on an exercise, if u feel u need more time between exercises then lighten the weight. dont do two 45 minute circuits in a week, its ok to go for a circuit of only 20 minutes as well
eat 6 small meals a day, the biggest one is breakfast and these are the only times u eat, drink TONS of water and remember that everything u drink has calories in it as well, except water, so let that be ur liquid
good luck, i hope this makes sense