I'm surprised that your relatives are unsupportive with so much diabetes history in the family. Maybe they are jealous that you've lost 3 stone already. You've got to keep your eyes on your own goals and not take any notice of their attitudes however much you love them. You have to put your own health first. I know that GPs are trigger happy when it comes to meds, but I suggest you ask GP for counselling because you are stressed.
I had it for 5 months once a week and it really helped to have a non-judgmental supportive ear to bend. You can talk to a counsellor about anything be it health stress, relationship stress,finance stress, difficult relies - ALL the things that stress you out. It's not about dissecting your mental health, it's about helping you cope with your life better. If the counsellor is good, it's always led by you, to help you, without any psychoanalysis stuff.