Chinese languages

hello this is my first post - hope everyone is well. I was wondering if anyone is in a similar situation to me. I am british born chinese who has been brought up speaking predominately English between my siblings and my parents as they wanted to improve on their english. My grandma lives with us and can only speak Hakka which means the only chinese I can speak is Hakka but not very well. Since leaving home for University my Hakka has deteriorated even more. I'm embarassed when relatives from HK call as i cant speak cantonese or mandarin. My parents can speak Hakka, Cantonese and Mandarin but the only chinese they speak to me and my siblings is Hakka.

Since finishing University I made a promise to myself to learn to speak Cantonese and even learn to read and write it. I would also love to learn to speak Mandarin but thats only if i'm successful with Cantonese!

I know it is a hard and slow process but I know i now have the time to focus on learning Cantonese. I understand basic Cantonese so I bought Colloquial Cantonese but it doesnt tell you how sentences are constructed. I was wondering if anyone has/is in the same situation and how they have gone about learning it. Due to student debts I need to make sure i buy the right book! Any advice on books/methods would be very grateful!

Sorry for the long message but any advice would be hugely appreciated!

Ann