lossing weight

i have been doing same diet for three weeks but the third week i got a surprise i gained 2.5 lbs. my teacher said water or mussle again.
then i found out alot about exersising if doing same routine after two weeks your body gets use to it and the effects stop.
i do a treadmill so every two weeks i must a just the speed and incline to feel any effects.same with weights my starting weight lift is a 120 lbs in two weeks i need to be to 140 my mass is 240 .
i was told i need to do five weeks of cardio to see any weight loss.
i have been working so hard on my diet. it saddens me to know i gained.
but by doing so i learned so much about exersising.
i work out very hard on my diet some would say dangerously and others says i am very dedicated.
i take two days of drumming , two days of zumba two days of palites and five days of water works.
my busy day is thursday. i have water works in the morning, palites at 4:45 to 5:30 , drumming 5:30 till six and zumba 6:30 till 7:30 .

plus i do bike and treadmill 6 days aweek.
i am on a 1000 calorie diet told to me by drumming teacher never go lower than that