By Harry Rutter Kourtney Kardashian is back at work after giving birth to son Rocky. Months after welcoming her son with husband Travis Barker, the reality TV star is busy filming scenes for the upcoming series of The Kardashians. Documenting the process on her social media, the 45-year-old got candid with her 223million fans on Instagram. Addressing her followers in an open and honest upload, Kourtney admitted she was “not quite feeling ready” for such a big shoot. Explaining her struggles three months postpartum, she confessed “shifting” her “mindset” in recent weeks after giving birth. For …