To tell that you are losing weight, observe your body in front of the mirror and if you notice tin bumps, it may be because of fat loss. Another way of finding out is by looking at how your clothes fit and close friends or family members who you have not seen for a while may also help you know whether or not you have lost weight. Check out http://www.ehow.com/how_7779738_tell-youre-losing-weight.html for more information.
you can gain muscle and lose weight at the same time making it so you weigh more. the best way is to look at the way your clothes fit and use a measuring tape to measure your waist line. hope this helps :)