Hi!!!!
Can I assume you are a girl? If so, we have a thread about how long it took us to get to losing and having our bodies change:
Girls Only 
Insanity is a HARD program and you should be proud of yourself for doing it! You must also understand that your body is in shock the first weeks and will retain water and acids as you get used to the jolts and the muscle growth.
May sure you track your progress in these ways: 1) Take pictures - you can't see in a mirror what you see in pictures! 2) Measure yourself with a measuring tape - you will see the inches melt away after a few weeks. 3) Do the fitness tests. You will see progress in all of these areas. I recommend you put away the scale for now.
You should also be eating more protein - that will help you build muscle. If you want help setting up an account to track, send me a message. You should create an account on myfitnesspal.com (it's free) so that you can track your protein and other macros.
Most of all - don't give up!!!! This is a super program and it will change your body if you keep at it! Sometimes the change starts from within - and I am betting you are converting fat to muscle as we speak

Beth