Coin M Perpetual Futures trading - Why is my position size changing?

I have been trading coin m futures for a little while and was in a large leveraged trade recently. As the price dropped my position size (not my margin size) increase dramatically, and likewise as the price increased my position size decreased. It seem that my profits are being reduced while my losses are being increase, making a already hard game even harder for the average trader. If this is true how can I complaint/fix it? My apologies if this has already been asked.