Oh, blech -- I'm sorry you're seeing that gain. It can be so very disappointing to see that stupid number on the scale. I started my weight loss journey by incorporating cardio (running) and weight training into my life 6 or 7 days per week, and limiting my caloric intake to about 1400. Well, I had gone from an essentially sedentary lifestyle to one on which I was getting a decent amount of caloric burn, and not eating fast food, etc., but it took me -- no joke -- 5 MONTHS to lose 5 pounds!! It was maddening, although it turned out I was putting on muscle mass.
How outstanding that you've dropped 80 pounds thus far!! That is simply wonderful. What you might find is that you have to work harder now to lose weight; your body is becoming efficient and acclimated to exercise, as mine has, and you may have to play with your caloric intake as well. I like that you're doing different/interesting activities for your exercise! That's the best way to keep things fresh and burn calories sneakily. Plus, you'll be one of the few young people who can actually dance.
Jessica