Weight gain bloating and acne with Mirena

I had the Mirena IUC inserted in May 2009, and for the most part I am happy with it.
the main concerns I have with it is since its insertion I have gained 10 lbs, and seem to have a constant bloating. I am just shy of 5'7" and normally weigh around 125 lbs. I am extremely active, i work out for an average of 2-2.5 hours 3-4 days at the gym, and I mountain bike an average of 25 miles on the weekends. I am 24 years old, no children. I used to wear a size 4, had for about 3-4 years. About 3 months ago i started to find my clothes snug, mainly my pants/jeans in the waist and thighs so i bought a few items in a size 6 and they fit me fine, maybe a little loose. Now 3 months laters I am progressing to a size 8! This is really starting to concern me.Is there anything i can do to stop gaining this weight. The bloating makes me I look as though I am pregnant!

My other concern is the Acne. I have always had combination skin, but i rarely suffer from breakouts...now I can't go a day without a pimple, bumps or a full grown break out on my face and they are starting to leave scars. I usially don't wear make-up and if i do its minimal, but I work in a highly visible field and it is embarresing to meet a client with breakouts and scars.

Thank you!