Sparring

Well, i have been sparring a bit, and also training quite a bit too. Mondays and wednesdays i have 2 hours of boxing training, and tuesdays, thursdays, and fridays I lift weights and work on tuning my body a bit. I have been boxing for around 5 months now, but just started going to the weight training center about 3 weeks ago. I have been eating a boxing diet, which my boxing coach is helping me out with.

The main thing I am getting at is the gym I go to, everyone I spar is MUCH bigger than myself. I am about 5' 7", and 145 pounds or so. There is one guy I box often who is about 5' 10 and 300 pounds(good at putting his weight into his punch, and knows when to throw them), another who is mabye 5'10 and 250(pretty fit) and another who is mabye 6' 190 pounds, who is extremely fit, and lifts weights the same place I do, and works out all the time. He has also been training for much longer than myself, and is way out of my leauge. I am faster than all of the people I spar, but dont throw as much of a punch. I am southpaw, but will at times switch to orthadox to counter/confuse them, which works for a while, but then the figure it out, and always counter me really good. Does anyone have any ideas about some things I could start working on?

If any of you have some advice, I would really appreciate it.

Thanks,

Luke