Starting all over again. Yesterday I fucked up my diet big time

I'm confused about what "diet" to follow but if one thing is true that is that the best diet is the one you can follow...so now...taking into account that I have to follow it, wait...that I WANT to follow it!!!, that I don't have time to cook (neitehr I'm good at it) and that I want to lose fat (my caliper said I have 38% fat... WTF?! I think I did it wrong, that is according to the measuremet overfat! and I can't believe I'm overfat weighing 48 (106 lbs yesterday) kilos even being so short! 1,57 (5"2)...
Anyways... I want to lose fat and maintain muscle....first things first and that is...losing fat first...
As far as training goes I want to do 5 days a week 50 minutes cardio (BODYCOMBAT) and 50 minutes BODYPUMP (That is weights but lots of repetitions with rather small amounts of weight)... I REALLY hope I can start today, I'm feeling still a bit sick, my ear hurts, I thought it was the throat but now I thoink it is the ear... FUCK! I hate these things...who doesn't?!
As far as diet goes.... I'm soooo confused.... If I want to get lean fast (and I really need the motivation), maybe the best thing would be to adapt the pre-contest diet... and mainly eating clean, that means fruits, vegetables and raw protein powder....it doesn't sound bad...as long as I still can have at least one banana a day!