wrong or its normal... lose weight and get weight back?

hello,
i started to lose weight and felt great cuz i saw results and im working on it really hard. did twice in a day the insanity, and watched what i ate.
still doin it good, but we got just a busy time atm so so i cant doin like i want. still doin my exercises and try to making a good food diary but my weight goes up again.

idk really about, but how i can get more weight if i dont eat more?
if i lose the fat but get fit with my muscles i get more weight?
should i try to go back to have done twice in a day my exercises to actually lose weight?

alot questions i know but im thankfully for any answer :flowerforyou:

starlet