weight gain 😡

I keep gaining weight and i have no idea why... i watch what i eat, i eat small portions, barely any soda and it just keeps packing on!! Its getting to frustrated and i feel nasty about myself. I order Herbalife shakes and going to start that soon. I dont know what else to do.. it makes what to cry. I went off the pill a month and half and started a new job in August. Im lost.. any tips would be great!