exercise advice

I'm in desperate exercise advice. I have a gym membership but I don't go. Well I could give a number of excuses about why I don't go. But I will save those for another day. Last night I was at my dance class and you know when you are looking in the mirror in a dance class you think you look fatter than you probably are. Well that is were my pity party came into effect. I'm determined before my dance performance to get a little more in shape. I have six weeks to drop a few pounds.
That is were you all come in. IF you could because list some techniques that you use or how many reps you do that would be great.
I just don't want to look like the fat whale dancing on the stage.